There are many things one expects when he is born and raised with a silver spoon in his mouth, and it shows in every little thing Tony does. His razor-sharp wit is honed over years of boredom, because really who can keep up with a genius of his calibre, and he makes no apologies for the scathing remarks he's been known to make—after all, what's the point of wasting time on apologies when he can just throw a handful of money at the issue and make it go away? He can be arrogant at the best of times and flat-out cruel at the worst, so he considers it a kindness whenever he spares anyone a second glance and spends most of his life believing that the whole world owes him everything they've got.
Everything changes after the Jericho… except, really, nothing does. It's almost painful to think about, how so much has happened to him and yet the world keeps right on spinning, not even allowing him the chance to catch up. All of the delusions Tony's held over the years are flushed out with the water up his nose and down his throat, crashing him into reality so hard that the whole universe tips and collides down beside him (or maybe it's just the repetitive near-drowning, he can't be quite sure). Three months he was gone, and by the time he comes back, things are just as usual as they were when he left—the iceberg to his Titanic of an ego. Tony had been holding himself together with the thought of people missing him: Obie, practically his father; Rhodey, the closest friend he's had in practically his entire life; Pepper, the girl he's very potentially in love with and for some reason doesn't seem to hate him in the slightest.
But then he's back, and Obie is the one who wanted him killed, Rhodey has spent the months telling himself to keep on keeping on, and Pepper, god, what's even going on with him and Pepper now? She was the one PA he's had who could keep up with his insanity and not stick a knife in his gut for it (which did happen, when he was twenty-two, so Tony has a rule that he will never again have a male PA). Was being the operative word, as it's only so much time before Pepper calls it quits and shoves herself back. He coaxes her into staying in a blind panic with words he's been tripping over for weeks now, but there's a rift between them that never quite heals after that.
He has nightmares of Afghanistan, of dank caves and car batteries, of tsunamis crashing into his lungs, of Yinsen grinning up at him even in death, and can't stand most of anything. Then there's Obie and Ivan Vanko and Justin Hammer, all conspiring together around a casket meant for him (somehow Tony can still be offended, even in his nightmares, at the fact that they plan to bury him in the plainest pine box imaginable). He wakes with the muscle memory of heart attacks and drowning and electrocution, mouth locked open in a silent scream, and he can't even take a shower without having a panic attack.
His sharp remarks are fuelled by fear now—even Obie was out to get him, Rhodey is acting more like a commanding officer than a friend, Pepper is practically his boss, he's only just starting to no longer be dying, and things are just too much, changing too fast, and he's the billionaire baby, he's Tony fucking Stark, and Tony fucking Stark is not supposed to have such a flimsy hold on the world. Nobody bothers getting close unless they're after his cash or his tech, and fuck them, they aren't getting either one, so when he isn't in the suit, he holes himself up in the house he's got in Seattle and blocks out the rain pounding down with Metallica cranked so loud that he's losing his hearing.
Pepper tries dragging him out to New York, but Tony attacks her with words harsh enough to leave bruises and she only brings him out of his workshop a few times a month to see the sun make him socialise. He's terrified, and she can see that, but she can only handle so much of him and he won't agree to sit down with a therapist, so what can she do?
Projects save him, in the end, things he can focus on with everything in his being. There aren't enough things in the world for him to do that he forgets the hells he's been dragged through, but at least he can withdraw himself from the memories for a bit. Some nights he even sleeps, without the atrocities that haunt him, because Pepper curls herself against his side and keeps him grounded. That's not enough, either, but most nights he can keep his head above the water long enough that it doesn't kill him.
It only makes sense that when Tony finally, finally, meets someone who's just as broken, who he knows shares the deep-seated self-loathing and agonising fear that he just can't shake… Well, he's infatuated.
One of the few things he retains from his LBA, his life-before-Afghanistan, is that he can have just about anything in the world with nothing but a glance at the price tag. Tony isn't used to being told no, which is difficult to blame him for considering his upbringing, so most of the time he forgets to even ask permission before doing what he wants.
Bruce, on some level, understands this. He knows the comfort of being around someone who forgets your flaws (it's hard to see the blue light on Tony's chest when his own green haze is so easily overlooked), and he enjoys spending the hours with his friend in their shared lab, losing themselves in work and security and easy companionship. He gets Tony's fuck-asking-for-anything-ever attitude and works around it with simple grace. In roughly no time at all, he and Tony know each other inside and out.
At least, they think they do.
Tony flirts nonstop, which is something he does even with You when he's bored and is practically his version of dogs sniffing butts, so Bruce stops noticing it after about an hour. Tony seems pleased with the retorts when Bruce can care to make them; before long every conversation they have is a challenge of wit, each trying to one-up the other with casual innuendoes and smooth come-ons, and neither one seems to find anything out of the ordinary here.
He's a very tactile person, and his presence is commanding even with all of the fucked up things in his head, so they find a happy medium somewhere between flicks of annoyance and full-on bear hugs where Tony can get all the physical comfort he needs and Bruce doesn't spend half of his time with a rope of stress knotted tight around his neck. Bruce learns to ignore the way Tony uses all five senses to learn—running the gamut from rapping his knuckles against things to chewing on them, and he nearly has a heart attack when Tony slides up beside him and licks a broad stripe across Bruce's neck, just to see what the other scientist would do—like how Tony learns to ignore the way Bruce mumbles insults under his breath when he's frustrated. They slide very smoothly alongside each other, more one single being than two.
When their repartee smashes a hole in one of the walls keeping a problem-child project from completion, Tony is so rapidly thrilled that he grabs Bruce by the front of his shirt and plants a kiss on his mouth. It's over almost instantly, and Tony seems as though he doesn't even realise that he did anything at all, so Bruce slots it into the just the things he does column on the mental map that is Anthony Edward Stark and forgets it.
It happens two days later, the instigator being that the Mark VIII is finally ready to go, and Tony appears thoroughly unperturbed with how Bruce goes rigid. And then again the next day, this time because Bruce brings lunch with him—shawarma, which Tony deemed a favourite after the Chitauri. And five minutes later, for no reason other than because apparently now he can.
Except he can't, actually, and Bruce nearly falls over himself in his rush to leave, and then doesn't come back for a week and a half. The armful of Tony he receives upon his return is expected, blessedly devoid of kisses, and they manage three days before the subject rears its ugly head.
Tony rolls his eyes a lot, Bruce notes absently, especially when someone is trying to tell him no.
No, Tony, you're my friend and that's it. (Obviously. Except for that part where you know you actually love me.) No, Tony, I didn't realise you wanted to get in my pants. (Seriously? I told you about a dozen times. Bruce, I'd hit that in half a heartbeat if I didn't think it'd hit back hard enough to knock me into last week.) No, Tony, I don't think this is a good idea. (I think it's a great idea, actually, and we both know who the smarter man is here.) No, Tony, I genuinely don't like you as anything more than a friend. ('Scuse me, you were flirting back just as hard, y'know.)
Bruce finally calls him a child and ignores him for the rest of the day, even when spitballs start hitting the back of his neck.
It takes storming up to Clint before dinner, momentarily terrifying the archer, and shoving his tongue down his throat for Tony to get it through his head that Bruce isn't interested. Bruce frowns over his shoulder, ignoring the stupidly self-satisfied expression Clint has adopted, and raises his eyebrows at Tony.
"Oh."
"Yeah. Oh."
"Hey, Stark? I'm okay with sharing."