Bruce Banner: FUCK YOU AND YOUR SCIENCE. He really just plain does not like him on principle. A Hulk could be useful in the right carefully orchestrated circumstances, but Bruce himself sets off alarm bells. He didn't agree to leave him alone for no reason beyond a badge and a spinny chair. He did it so he has a legitimate explanation why he won't interact like he does everyone else. He's also 75% of the reason that Loki wants to do something terrible to Tony in order to save him. He needs an ally like Iron Man here, and he needs enough positive regard to counteract any reasonable influences that might slow that process down if he somehow needs to tap Tony for a plan on the fly.

Okay, gimme a sec and I'll do Willow's, too.