Pepper has always reminded him of a machine.

She'd punch him if he even thought of mentioning it, of course. Especially if he told her it was his favorite thing about her. Or favorite things, really. The way she glides, ball-bearing smooth; other girls slink, strut. Her hair is smooth sine curves. The way she dresses… He'd scribbled down a formula for it, once. Jarvis can predict with 92 percent accuracy whether she will wear brown or black on any given day, and even predicts accent color correctly more than 80 percent of the time. Then again, Jarvis has an inside track. There's a line in his code that instructs him to assimilate Ms. Potts' erratic shifts from professional to sassy.

That's what no one seems to understand. A good machine isn't predictable. A good machine isn't stiff. It takes input, and if you've tweaked it just right, it will spit something back that you don't expect. Like the time he'd caught her giggling, teaching Butterfingers to apply toenail polish. The look on her face when he'd arranged for a proper in-office pedicure the next day is still good to summon a smirk when she's snippy. Which is often, and not just because he's incorrigible. She pushes pushes pushes to the logical conclusion with the implacability of an algorithm.

He's always pushed back, fiddled around the edges of her responses until he knows what will get him a poisonous look and what will earn a slow smile. But just lately… He has to override himself, override years and years and countless conversations and slow meaningful blinks, countless come-ons that have worn a groove in his behavior. That was good for them, for the hundreds (come on, now, Stark, hundreds? But then again, maybe. He'd have to have Jarvis count them) of little one-off applets that were fun to play but far too easy to figure out. Unless they weren't. Unless every single one of them thrummed with Pepper's complexity if only he'd taken the time…

This, this was why he hated down-time. Even an elevator's worth of silence was too much. Never did him any good, no good at all, not when his fingers itched to fiddle with the new circuitry he'd been working up (Rhodey was gonna shit his pants) and his ears itched for crashing drums. Shouldn't have left her behind, not even to conquer the mountain of paper that almost swallowed her pin-neat office. Should've brought a goddamn ipod. Silence always got him stuck in a loop, an insurmountable loop that was oh-so-different from the days where one song on repeat was the only thing that would do. And now, god, now… Now it was so much worse than pop existentialism and the bone-deep tired that hit when there was no one around to watch him be Tony Stark. The things that rattled around in his head now were worse, infinitely worse and far too real.

Ding. At last, doors open and the whir-hiss of the workshop and pure fun of the design team meeting push it all back out of his head, straight into nothingness where it belongs.