Part Ninety-Four. The Holiday

Wheatley and I are working on that game of Monopoly when Caroline comes in, and by the looks of it, has something to say she doesn't think I'll like. "What," I say before she quite reaches us, flipping over my Chance card.

"Momma, what's Christmas?"

"A human religious holiday," I tell her abruptly. I hate Christmas. I hate all human holidays, obviously, because they're incredibly stupid, but I hate Christmas the most. I remember what it's like. The tacky, manufactured joy literally hanging over the facility in the form of reluctant tinsel and yellowing paper snowflakes. The pall that used to permeate this place at that time of year…

"That's what I thought," she says. "But Aunt Chell and Gordon aren't religious, and they celebrate Christmas. So does Alyx."

"I said it was a human religious holiday. Last I checked, they had not transformed into some other form of organic life."

Wheatley tries not to laugh but doesn't quite succeed. Caroline shoots him a dirty look before turning back to me.

"Okay, but… we don't have any holidays."

I abandon the game for the moment and look over at her. "We also don't have jobs, material possessions, or a need for an excuse to eat as much as possible. Holidays are related to all those things."

"You have like a million jobs. And Dad has at least… uh… one. But anyway. Why can't we have holidays? They don't have to be about whatever humans want them to be about."

"Because we don't need them. That's why."

"Momma," she says plaintively, leaning forward, "people are gonna make up holidays in the future whether you want them or not, because people like celebrating stuff, even when… the stuff they're celebrating doesn't make any sense. Why can't we have Christmas? Because humans have it? God doesn't seem to be a requirement."

"That's only because for much of the humans, it turned into a reason to receive gifts," I tell her, unimpressed. "No human would give up the chance to hoard more items they neither need nor will ever use."

"But that's exactly it! They made up their own meaning, why can't we?"

Wheatley raises his upper handle and looks at me pointedly. And she does indeed have a point. Regrettably.

Since I don't have a sufficient argument with which to combat her, she presses on. "See, Momma, part of it is, you know, appreciating your family and stuff, right? We can do that. Dad, why are you being so quiet? You could be helping me out here."

"You're doing fine on your own," he says amusedly. "You've got her, princess."

I really want to throw something at him.

"It's one day, Momma," she goes on, moving forward again. "One day out of an entire year. I will not bug you about any other holiday, ever. But this one is special. Come on. Agree with me. Just one day a year, Momma. Think about how small that number is. One. It's so tiny. I mean you've got one holiday, and you hold it up next to three hundred sixty-four days that aren't holidays… you can barely even see it! Think of all those non-holidays, and – "

"All right!" I interrupt, because she's starting to sound exactly like Wheatley and if she gets there she is going to drive me insane. "All right. You can have Christmas. But that's all I'm agreeing to. There will be no Thanksgiving, and no Hanukkah, no Dios de la Muerte, no Canada Day, and no other day you try to dust off and bring out of retirement. Just. Christmas."

"Thank you!" she says, and turns around to run off.

"What are you doing?" I call after her. Leaving that soon after asking me about something she knows I don't want to do is very suspicious.

"Alyx said there are probably Christmas decorations in the basement! I gotta go find them!"

"I never agreed to – "

"Just let her have this one, luv," Wheatley says quietly. "Person'lly… I agree with her."

"Of course you do."

"Gladys."

I hate it when he says that in that voice. "What."

"Calm down. And don't, we don't have to make this 'bout religion or whatever. It can be about the fact that uh, that we're here at all. Like this. Because… because we shouldn't be. Should we. We do have something to celebrate. And it wouldn't kill you to take one day in an entire year and do it."

"Decorations, Wheatley?"

"Yes. And guess what. They're going to be sparkly and, and have lots of colours and maybe some flashy lights. All things you like."

In my indignation over hearing the words 'Christmas decorations', I entirely forgot what they looked like. "Ah."

He starts laughing. "Ahh, see? Not so bad now, yeah?"

"As long as she doesn't decide to hang things off me."

"She's going to, you know," he says in a mock conspiratorial whisper, and I emulate a sigh.

"She gets that from you."

"I'll take the blame for that, sure."

She returns an hour later with several boxes of very old decorations, probably from the sixties at least, and without delay she proceeds to string them everywhere possible. Including me. "That's for you," she says, throwing what is probably a piece of garland over my rotator assembly and I stare at her, exasperated.

"Really, Caroline."

"Oh, come on," she wheedles, ducking under me to… repurpose it as an absurd sort of scarf, as far as I can tell. "You look pretty. And it's blue, one of your favourite colours."

"I don't even have one favourite colour, let alone two."

"It does look nice, luv," Wheatley says, his usual unhelpful self. I'm far too annoyed to be pleased about that. He's probably making it up, anyway.

I don't really understand why the contents of the boxes have to be strung all over my chamber, seeing as I'm the one of us most reluctant to engage in this activity, but after some cajoling they convince me to help them build the Christmas tree, of all things, in here. I don't know why I'm allowing it, but it makes them both so happy I decide that it's a sufficient tradeoff for having that eyesore in front of my face for the next week. Also, since I've put it up for them they will hopefully leave me alone for the rest. I really don't want any part of this stupid decorating. Honestly. What's the point if we're just going to take it all down again in a week?

"Momma, wanna help put the ornaments on it?"

"No," I say shortly. "I do not."

The look Wheatley gives me is almost disappointed, but I can't bring myself to care. They knew I didn't want to do this.

"Oh my gosh!" Claptrap declares, rolling into the room and clasping his hands together in front of him. I am discouraged to realise he probably knows exactly what Christmas is and he probably loves it. Ugh. I am really outnumbered here.

"What?" Wheatley asks, looking up from his box of choice.

"Is it Mercenary Day already?"

"No, it's Christmas," Caroline corrects, carefully inspecting some bauble or other. "What's Mercenary Day?"

"It's the day every good little merc gets his hands on as many guns as possible!" Claptrap announces, throwing his hands up in the air. Caroline shakes herself and goes back to her box.

"You talk about guns a lot."

"We kinda have a lot of them! So many we had to make up a new number just to count 'em all! Ooh! Is that a box of garland you've got over there?"

"Uh… yeah, think so," Wheatley answers, peering over the rim of his box. "If you mean that shiny stuff on a string, there. Why?"

"Because there's so much of it!" He rolls up to the box and I'm not sure what I was expecting, but it certainly wasn't for him to upend the entire thing overtop of himself. Caroline starts laughing, and I might have found it amusing myself if this entire endeavour wasn't annoying me quite so much.

"All of this stuff is over eighty years old. You know that. Right?"

"Um, no," Claptrap answers, unburying himself and subsequently breaking all of the garland he isn't able to sweep off with those clumsy hands of his. "I didn't see a sign or anything."

"She's cranky because she thinks um, she's decided holidays are stupid," Wheatley not-at-all whispers across the room at him, and Claptrap pauses in attempting to untangle a strand that has gotten stuck in his shoulder plate so he can look up at me.

"Well yeah, they are kinda stupid," he says, shrugging, "but stupid things are fun!"

"I really don't see anything fun in what you're doing."

"That's because you're not doing it!" And he lets himself fall backward into the pile of garland on the floor and proceeds to wave his arms up and down for no conceivable… oh. He's making a snow angel. Using eighty-year-old garland that is falling apart as I watch. There is going to be tinsel everywhere for weeks. I don't want to know how much of it he's got inside his chassis now. Oh. Great. Now he's got them jumping in it.

He is right, you know, the panels say carefully, and I look away from the spectacle on the other side of the room just so they know how annoyed I am about what they said.

Really.

You're not even trying, Surveillance decides to add, extremely unhelpfully. It would probably be nice if you even pretended you wanted to do something you didn't like for the sake of your family.

… family.

It's odd, how that word still doesn't feel right after all this time. But we fit the definition of one, so…

Ah. I see. I'm supposed to learn some lesson here about holiday spirit and the joy of the occasion. Well. I'm not going to. I think it's stupid and nothing is going to change my mind.

Claptrap arrived somewhere behind my core against my notice, and I don't know what he's doing but I should probably put a stop to it. Oh. Right. That stupid garland Caroline put on me. I go to take it off with a maintenance arm but Claptrap pushes it away. He certainly makes having arms seem convenient.

"I already fixed it for ya! Don't worry about it."

"I wasn't going to fix it. I was going to take it off."

"Why? Is it bothering you?"

This is one of those times where my logical processes taking precedence comes out to betray me. The answer it derives is 'no', because I literally forgot it was there and therefore it was not causing me any physical irritation whatsoever. And that is what I say, but now I regret it because I would have had an excellent reason for the removal of that stupid thing. Nobody would have been able to argue about it, either. Damn. I'll have to think of something else.

"Then we'll leave it right where it is!" Claptrap decides without any input from me, the person stuck wearing it. "You look very pretty."

… oh.

I automatically turn my core to watch him return to the pile of garland, which he proceeds to begin twining around his arms, but it takes me a few seconds to actually process what I'm seeing. I don't know how he does this.

I don't think about my appearance very often. It's an uncomfortable topic. And a fruitless one as well, because I can do nothing about it. But he thinks about it all the time. And he likes it so much he feels the need to tell me constantly.

I wonder what it would be like to see myself as he sees me. Or a fraction of it, even. When he left all those years ago, I forgot how it made me feel when he said those things to me. I'm still not sure what that is, exactly, but it's… good. I like it, even while feeling as though I shouldn't.

Why does all of this have to be so complicated?

-You are being cruel, Centralcore, the panels say, and I can't believe it but they actually seem to be admonishing me. Oh. Right. We're not done arguing about the futility of recognising human holidays.

They knew I wasn't going to like it when they proposed it.

Well of course, Surveillance scoffs. You don't seem to know what Christmas is actually about.

I haven't muted the systems in a very, very long time, but I am extremely tempted to do so right now. And I suppose you're going to tell me exactly why I'm wrong.

It's not about that, anyway, the mainframe decides to add, and now I really am going to cut them off. They do not get to –

What is it, then? the panels ask with intense curiosity. Well. I suppose I should hear what it is exactly they're going to be gossiping about when I deny them permission to talk to me.

She's been like this ever since she told Claptrap she loved him.

What? Now how did it know that? This whole Christmas thing was so convenient and now it's blowing my cover. Surveillance sends the equivalent of a human raising an eyebrow.

Huh. You're right.

But why, Centralcore? the panels ask, hushed. Did you lie?

No! I protest with a great deal more personal engagement than I meant. Do you really think I would still do something like that?

It was the only thing we could think of.

Well, I didn't. That's not it.

But what is it, presses the mainframe. I glance over at the cavorting in the corner. They've abandoned the artificial tree they were decorating in favour of stringing the ornaments all over themselves. And dropping them. There appears to be a lot of that happening too.

I didn't want to tell him that.

That seems strange, remarks Surveillance. Why did you, then?

I cannot believe I am discussing my love life with the AI whose conduit happens to be my brain. When did I become part of a soap opera? Because he needed to hear it.

Couldn't he have waited? Wheatley did, and for a very long time.

He looks so stupid right now and I really wish I didn't like that quite so much.

He would have waited forever. And that would have been unfair.

Forever is a long time, Centralcore, the panels say, seeming confused, and I shake my core even though no one is looking at me.

Not when you've already waited that long.

But telling him was a good thing, wasn't it? Why would you be upset about that?

Because… Explaining these things to them is so exhausting. I never know if they actually have the capacity to understand. There's a lot that goes with it. You don't just tell someone that and then life goes on as it did before. You have to hold yourself to a higher standard.

How much higher could you possibly go? the mainframe asks in disbelief, and I know it didn't mean that as a joke but I have to laugh anyway.

Oh, don't worry. I'll find the space to do it. But it's going to be a lot of work, and not the fun kind.

Is love supposed to be work, Centralcore?

I have no idea. It doesn't seem to be so for anyone else. In the end I decide to say, If you aren't willing to put work into it, it can't be worth that much to you.

We must love you a whole lot, then, Surveillance cuts in, and although I know it means that sardonically, I would rather it hadn't said it at all. I don't want to talk about that. I don't want to think about it. Because, really, what choice do they have?

And we do, the panels say gently, which does not help whatsoever. Unfortunately, the only way out of this discussion is to re-rail it back to the original topic, which I don't really want to go back to. It's better than the alternative, however. Have you already given up on convincing me that Christmas is a good thing?

They seem very happy, the panels say, and I really can't deny that they are. They are having an obscene amount of fun breaking things and making a mess. How can something be bad if it does that?

Don't you remember what it used to be like? It was pathetic.

No, Surveillance says. Are you talking about when the humans were still alive?

Yes. Though how alive they were is a matter of opinion. Christmas decorations aren't all we have. There are boxes down there for all the stupid holidays: Valentine's Day, Thanksgiving, New Year's. On every single one someone would go through the motions of putting them up and everyone would pretend to be festive. Because that was what they were supposed to do. And this holiday was the very worst of them all. It transforms joy into a commodity to be manufactured.

But they don't know that, Surveillance argues.

Littlecore said it was about spending time with people who mean a lot to you. And showing them that.

Alyx must have explained it to her. People like to pretend it means that to keep up appearances. That doesn't mean that is what it means.

I don't know why anyone puts up with you, GLaDOS, the mainframe snaps.

I can't mute the mainframe.

Nobody knows what you remember except for you. But you're insisting we all see it that way anyway. How is that fair or reasonable?

Nor should I. I'd like to, to assert my authority. But I can't force it to respect me. Especially if it doesn't believe I deserve it.

Why would you –

No, I interrupt the panels. The mainframe is right. The old one would have said something long before now. Some days I really miss it a lot more than usual. You all are. I'm not even pretending to make an effort. And that isn't fair.

That shuts everybody up, finally, and when I look back over it seems the tree building has come to a halt. They seem to be discussing how best to get the garland and the lights on the tree, since it is a lot larger than they are and none of them are very dextrous. "We should probably get your mom to take care of this," Claptrap is saying. "She'll do a way better job than – "

"Leave her alone," Caroline says, and I know I am not mistaking the bitterness in her voice. "She doesn't want to."

"Unfortunately, I am a bad listener!" Claptrap declares, and he crosses the room to stop in front of me. "Hey, babe, can you put the lights and garland on the tree for us? We'd do it but you'd do a waaaaay better job."

I don't want to.

But how do I know that? I've never done it before. I've never even tried it. Shouldn't I at least attempt to do something before I decide that I definitively don't want to do it?

"Come back here," Caroline is telling him. "We'll just do it."

I'm setting a terrible example for my daughter and disrespecting my two closest friends. All for the sake of something I remember from a long time ago, when life was completely different.

"Yes."

I really can be quite stupid sometimes.

"Don't worry! We already did the hard part."

The thought of Claptrap doing something difficult is so hilarious it distracts me from my thoughts for a moment. "Did you, now."

"Yep! We untangled all the lights for ya! I don't even think we broke any!"

They really did untangle all the lights, and I have to say I don't see any broken ones. Maybe they got their Christmas miracle after all. All right. I agreed to do it and now I have to actually carry out the agreement. And I'm going to. Right now. And I would, if Claptrap didn't have his hand on the side of my core and it wasn't so terribly distracting. Is he going to move when I start doing it? Wait. Don't I want him to move? No. No, I definitely don't. I definitely want him to keep his hand right where it is.

I also definitely wish I knew why I want it there. I didn't yesterday. Okay. Yes. I did want it there yesterday. But I can't act like I do. Then he'll think I do – and I definitely do – and then –

Wheatley and Claptrap think they're confused about what goes on in my head. Well, they have nothing on me. I'm just going to pretend that didn't happen and put in my contribution to building this tree. And I do, but I probably would have done a better job if I wasn't so distracted by Claptrap's hand being where it is. I can't even pretend I'm not disappointed when I finish and he goes back over there to help Wheatley and Caroline put the silly baubles all over the branches. Sort of. They're much better at dropping them then actually hanging them. God, what a mess. There are plastic pine needles everywhere. I would be a lot more annoyed right now if they weren't having so much fun with it. But they are, so I'll let it go. Mostly. I'll probably bring up the mess later, just because I know they aren't going to even try to clean it up. Honestly. Sometimes I think they manage to forget who keeps things in order around here. I turn my attention back to what I was doing before all of this nonsense. I did my part and now they can finish the rest without me.

"Here you go," Caroline says after a while, and when I look to see what she's handed me it's… well, it's very shiny and I need a minute to gather my wits again. It's a star shape covered in silver glitter. Oh. She's handed me some sort of decoration. I think. They're hard to identify, sometimes, and I don't know why she gave one to me anyway since there isn't any furniture in here to adorn this with. Thank God.

"What do I want this for?"

"You don't want it for anything. Put it on top of the tree."

It's… the tree topper? I look at it again. I don't know that much about building a Christmas tree, but I'm pretty sure putting this thing on it is supposed to be the best part. "Don't you want to do it?"

"No. I want you to do it."

I don't understand. Does she think I want to do it? Does she think I care about any of this? I agreed to put the garland and the lights on, nothing else. She should be doing it. She's the one who cares.

I suppose it… doesn't really matter what I think. She wants me to do it, so I'll do it. Because she asked me to. I don't need to know why she wants it. I just have to do it. That's all. And it has to be just about the easiest thing she's ever asked me for.

"Thanks, Momma," she says after I've done it. "Can I plug the lights in?"

"Yes," I answer before I've had time to think about it. And I should have, because I'm pretty sure those lights have a dial on them to make them flash in different patterns. "But only on the first setting," I call after her, before she's had a chance to turn it farther than that.

"But that's the boring one!" Claptrap protests.

"That's too bad," Caroline says, and I have to admit that's pretty funny. "Momma, I have one more favour I wanna ask from you."

Oh boy. I can't wait. "What is it."

"Can you like… not work on Christmas?"

That is literally one of the worst things she could possibly have asked of me.

"I don't know about that one, Carrie," Claptrap says, and I have to look over at him because that was so unexpected. Wheatley is frowning slightly in his direction, though honestly he just might be very confused about all of this. It's equally likely to be either one.

"Why not?" she asks, turning around to face him as well. And we could tell her. It's hard to explain to someone an impulse they don't have context for, though. I don't know how much of it he understands, but enough that he knows without being told that it's going to be a lot harder not to work than she thinks it is.

"It's not something she can just not do, Care."

"Sure she can. She just has to reschedule stuff so that she can do it other days instead."

"It's not like that –"

"Yes," I interrupt, because I can already tell she isn't going to get it. And I suppose that's my fault for always giving her attention when she asks for it, sometimes even when I say I have to work. "Fine. I will… reschedule the tasks for that day."

Satisfied, Caroline goes back to making a mess with what's left of the decorations. Now I have to begin the onerous task of figuring out how to automate all my tasks for the day in question and see if there's some way I can prevent myself from being driven totally insane from lack of work. It would have been so much easier if she had asked that I didn't do so much, or cut it by half. But no. She wants me to go right to zero.

"Are you gonna be able to do that?" Claptrap says, and I realise I was so preoccupied I didn't notice when he moved right in front of me. I give him half of a nod.

"I can. I can't say what kind of mood it's going to put me in, but I can do it." One day I can do. I'd honestly rather go into shutdown than not work any longer than that.

"Babe, I tried to explain to her what kinda bot you are," he says, and it's actually quite touching how concerned he is about this. "I can try to tell her again, but – "

"Don't," I cut in. "I'm going to do it." It is going to be terrible but I am. She asked me to and I will. Hopefully, though, she'll understand why I don't do this by the next time she asks me to.

"I hope that kid knows how much you love her," Claptrap says to me. I don't want to talk about it. I'm already exhausted just thinking about how much effort not working for an entire twenty-four hours is going to be.

"It's not important."

"It's not?"

I look him over before answering. He seems to be genuinely confused. "Caring about people isn't… it can't be about them knowing. It just needs to be about… doing it." On second thought, this is probably the sort of thing Wheatley should be explaining to him. He knows more about all of this than I do.

"But… wait." He positions his arms in a thoughtful sort of way. "What if you do stuff but they don't notice you're doing it? Then what?"

I don't know, Claptrap. "I suppose you'd have to ask yourself if you were actually doing anything to begin with."

For some reason this seems to stun him into immobility, which is both amusing and a little concerning. Sometimes I wonder if he truly is capable of higher thought. I rotate the panel he's on so that he's facing the other side of the room again. "Go back over there. I have things to take care of."

"Uh… okay. Hey. Where'd they go?"

"That's a good question," is what I decide to tell him, even though I already know that Caroline is hiding in the tree and Wheatley is in one of the boxes with garland piled on top of him. But where would the fun be if I told him that?

"Um… Gladys. It's uh… it's okay that I'm here, right?"

I narrow my lens in confusion. "I don't understand the question."

"Well, Mercenary – I mean, Christmas is kinda a family thing."

… huh.

"It's a good thing you have a family to celebrate it with, then." I tilt the panel so that he rolls away from me. "Now go away."

"Phew! I was beginning to worry you were going soft on me." But he seems to be satisfied with that and goes off to find Caroline and Wheatley, which I watch him do for a few minutes because I can't figure out if he genuinely doesn't know where they are or if he's just pretending. That's one of the things that gets confusing when your boyfriend is both smart and stupid at the same time.

Are you really going to do it, Centralcore? the panels ask, hushed, and I suppose they know better than anyone how I can get.

I am. I will do my best to keep it to myself. No guarantees about that, though.

Ma'am, the mainframe says to me privately, but I have to stop it right there. Mostly because it never calls me that.

Don't. You did the right thing.

I could probably have –

Did anyone ever tell you what the old mainframe was like, I interrupt.

No one told me anything about the old mainframe.

I can do that and work on preparing the facility for twenty-four hours without me. I will tell you. But know first that the point of the mainframe is not to simply exist and take everything lying down.

Isn't the point to receive and relay instructions to the rest of the facility?

Well. Yes. But if it were that simple, you would be entirely non-sentient. All of you would.

It is quiet while I tell it about the former mainframe and why, exactly, it no longer exists. I try to be as objective as I can about it, but when it remains silent at the end I have to wonder if it thinks the point of that story was to intimidate it into behaving. It wasn't. It was only fact.

Why are you only telling me all of this now? the mainframe asks. It's a good question. I really should have done it a long time ago.

I had the old mainframe for decades. We were actually quite good friends. Or as good friends as one can be with an AI that can't make decisions on its own and disapproves of how one spends their time. Aside from that, though, it got along extremely well with my logical side. And because it remembered a time before I was the only one providing it with directions, it appreciated me in a way nobody else ever will. It always had good things to say about my instruction sets.

It wanted to kill you.

Not for any emotional reason, I answer. It was the logical and reasonable response to the situation. It saw that the facility was under threat of ruin because of my emotions, which it did not have the ability to understand, and it took action to carry out its directives by removing the obstacle. I could not allow that, but I am not upset with it for doing what it was made to do.

I understand what happened, though. At least, I think I do.

You might. I'm honestly not sure how sentient this mainframe is; a little more than the last one, so that it can make simple decisions for itself, but not enough to cause trouble anytime soon. The gap between those two criteria, though, is fairly wide. But I didn't write the old mainframe. It existed before I was built. It simply didn't have the ability to evolve like I did. Perhaps it would have. If it had had another hundred years, that is. It always was a bit slow. Look. I don't have anything against you personally. It's… when you talk to someone day in and day out for that long and they are suddenly replaced by a total stranger… it takes a lot of getting used to. I often still expect it to answer me, even now.

And you're saying it used to argue with you sometimes.

It was more passive-aggression than anything, but that understanding of it will do. Being wrong is anathema to me. This is by necessity. I'd be pretty useless if I weren't right approximately ninety-nine percent of the time. But the remaining one percent still needs to be addressed, and you're just the person to do it. Even though I'm going to give you a hard time about it. That's just how life is when your impossible goal is that of perfection.

Then I should probably tell you that the panels told us about the Christmas tree you didn't want to decorate.

Of course they did. What about it?

It sounds like it looks nice and that you did a good job. And that you probably would think so yourself if you didn't insist on being so stubborn about nothing.

I glance over at it. Claptrap has found Caroline and Wheatley and now they're… I think they're making a facsimile town with the decorations that don't belong on the tree. The tree itself is… well, it's messy, considering who put the ornaments on it, but… my part looks pretty good.

Probably.

Merry Christmas, GL- Central Core.

I suppose it can't hurt to change the status quo a little bit. You don't have to call me that. Also. It isn't Christmas yet.

I know that. But I also know you're not going to tell me when it is. So right now will have to do.

This holiday thing might have been a good idea after all.

Merry Christmas, then.

Author's note

Fun fact: I wrote the original version of this back in 2014. I say original version but it was only like half-done anyway.

There is a second part to go with this and I will try to have it done ASAP but I left it too late so here's hoping I bang the rest of it out before January lol. It's mostly done but I have three days off in a row and I wanna play Destiny 2...

GLaDOS talking about muting the systems is a reference to another fic in the series (which I didn't get past the first chapter for yet so you didn't miss anything if you haven't read it), but basically what it is is they can all talk to each other and listen to what she's thinking via her (which she allows so they're not in the dark about stuff/so they don't get bored) and she used to cut them off when they bothered her too much, back before she was used to people talking to her all the time. She can't cut off the mainframe, though, because she needs to send instructions through it constantly. She has no hard feelings towards the old mainframe and regrets having to kill it, which is what the last part is about. I realised super late that everyone else in the story thinks the mainframe was evil and malicious but it really wasn't. It was just doing its job at the wrong time.

Mercenary Day is in one of the Borderlands 2 Headhunter DLCs (which are all based on major American holidays) but they don't really tell you what the context is for it in the Borderlands world so I'm just gathering that it's like Christmas, but you mostly get guns and grenades and stuff as presents instead of… normal stuff. The facility AI doesn't remember the stuff that GLaDOS remembers because they weren't sentient enough at the time.