"Big man in a suit of armour. Take that away, what are you?"
Those words had hit him like a ton of bricks and hurt much more than he let on. And the look of repulsion Steve gave him...
But perhaps he had deserved that. All the snarky-ness and attitued he had been giving him since his arrival.
He could remember the stories his father used to tell him. Of how fondly he had spoken of him. He wanted to hear that same fondness when he spoke of Tony. He never did. And perhaps he resented that. Seeing Steve was a reminder of what he wasn't. Of who he hadn't become. Some whom everyone seemed to like. Someone so perfect and nice it pissed him off.
He wanted to see the man's character falter. So Tony did what he does best and acted like a petulant child until Steve gave in. When he did he wasn't prepared for what came next. It had backfired on him. Those damn words. He played it off as nothing, making a smart reply instead. He didn't want anyone to see how deeply he could cut him. From anyone else he could shrug it off. But from a man he had so deeply admired and admittedly still does, it was almost too much to bear.
And now he sat there hating Steve for hurting him, but mostly hating himself for deserving it.