It probably stems from her parents' discipline methods, which they had employed from birth to her eighteen birthday. You screw up; you get extra chores. The Gilberts, for all their flaws—and they had many—were reasonable and fair in the domestic justice department. So Erin had spent a significant portion of her childhood mulling over her behavior while helping her father mow the lawn, or drying dishes with her mother.
Those memories are precious to her now, because she can zero in on them and pretend that she had a childhood filled with simple moments like those, one that hadn't been marred by a ghost, cruel nicknames, and unhelpful and unnecessary therapy.
Erin has been cleaning the firehouse for two weeks. It has been two weeks since the Ghostbusters saved the world, and she has filled her time with other people's laundry and dishes. She tries to keep the sink clear at all times, which is no small task when Holtzmann cannot be trained to use the same glass every time she wants more Root Beer, or rinse the chocolate syrup out of her ice cream bowl, or—basically Holtzmann is infuriating, but Erin finds her endearing, which is confusing, and she just loves her new friends a lot, okay?
She sorts their laundry and leaves it in neat piles outside of their doors.
She wipes off the counters and sweeps the floor, and she tries to do these things when the others aren't around because she is vaguely aware that her compulsion is strange and she doesn't want to draw attention to herself.
But she just feels so goddamn guilty.
She has this new life, with three really solid people in it. We're not counting Kevin, because he means well but he doesn't compare to the girls. Her girls, who look at her like she is smart and special, who laugh at her stupid, nerdy jokes, and ruffle her hair, and buy her favorite ice cream flavor because they see it when they are out grocery shopping and they are thoughtful like that, which is all just wonderful.
She hasn't earned this, she thinks as she washes a bowl covered in dried oatmeal, which is Patty's mildly annoying habit.
Abby had loved her. Abby was devoted to her. And she left Abby in the dust in favor of a decent reputation, and a career that wouldn't have truly made her happy, even if she had gotten tenure.
Erin isn't sure how she lived with herself all of that time— how she justified ditching the one person who had allowed her to truly be herself.
And now she has Abby and then some.
So she cleans as penance, because all of those years of therapy didn't teach her shit about dealing with her feelings.
"You know," a voice says from behind her, "if Patty had to do that herself, I can guarantee that she'd stop wandering away without at least rinsing it out."
Erin sets the bowl down, grabbing a towel to dry her hands as she turns to face Abby.
Abby's face is gentle, and familiar, and it suddenly makes Erin want to cry.
"I don't mind," she says with a weak shrug.
"C'mon, Erin," Abby folds her arms, "you've been scurrying around here like the hired help since we moved in. I know you like things neat, but you weren't like this with any of our apartments."
Erin feels dizzy. She feels like this sometimes, when she is in close-proximity with Abby: like she can't believe Abby is standing there, looking at her with compassion and maybe a touch of exasperation. Like she used to. Like Erin had longed for her to when she allowed herself to indulge in the memories of their friendship while she was working at Columbia.
She is crying now—damn it—and Abby moves towards her with her arms out, but Erin steps back because she doesn't think she can take Abby's comfort at the moment.
"I'm sorry, Abby," she chokes out.
"For what?" Abby looks comically confused, and Erin will probably laugh at the image of her wide eyes and open mouth later, after she is done sobbing.
"I'm so sorry," she wipes her eyes.
"For lack of more information," Abby places a steadying hand on Erin's shoulder, "I can only repeat: for what?"
"Leaving you, being the worst best friend in the universe, all of it."
Erin tries to control her breathing, but the hiccups and sobs keep bubbling out of her like carbonation.
"Oh, Erin."
She can see Abby connecting the dots—the two weeks of sheepishness, crazed emotions, and the cleaning—and she feels like an open book with no subtext.
"Okay," Abby runs her hand up and down Erin's arm, "first of all: you were never the worst best friend in the universe. I think that honor goes to those two girls in West Virginia who killed their best friend because they 'didn't want to be friends anymore.' Remember them?"
Erin laughs and buries her head in Abby's arm, a little ashamed of her hyperbole habit.
"And sweetie," Abby lifts Erin's chin so that she can look at her, "I think you may be forgetting that you jumped into a portal for me."
"I can't just expect that to erase the past," Erin played the fabric of her friend's shirt, "one grand gesture, and all is forgiven?"
"You can't, but I get to make that call. And I say it is."
"Really?" Erin would have winced at how childlike her voice sounds if she wasn't so excited by the prospect of being properly forgiven.
"Yeah," Abby pulls her in closer, "you kind of outdid yourself, Ghost Girl. We're good."
Erin melts into the embrace and finally stops fighting the feeling of elation that she has her best friend back. The relief washes away her need to wash the rest of the dishes in the sink. Except hers, of course. She will wash those.
"Is this strictly a two person hug, or can I join in?"
"Holtzy, leave them alone. Clearly they are having a moment."
Erin untangles herself from Abby so that she can look at her two new friends. And they are beautiful. She can't help but smile.
"You guys are okay, right?" Patty asks.
"We're great," Abby, answers, nudging Erin with her elbow.
Erin clears her throat, ready to make an important announcement.
"I think we should make a vow to rinse the dishes as we go. It'll make things so much easier. Can I get an amen?"