Steve really fights not to roll his eyes at Tony. The flirting won't drive him away; he should know that by now. The more he tries to project it, the harder Steve's going to ignore him. Besides, he's caught Tony anyway, and as he tries to deny it, Steve cocks his head to the side as if to say he's not selling this very well.

"Right, that's why we're basically arguing over nothing," he says. "Why you get all up in my space just to push me away." Which is why he asked what the other Steve even did to him, to warrant this. Because yes, they're different people, all four of them, but they also all know each other well enough to get under each other's skin faster than pretty much anyone else. Zemo took years what Tony and Steve perfected in minutes.