Steve is getting a little frustrated with Tony. There's that whole team player thing, or lack there of, and Tony simply being Tony Stark. He watches carefully to see what he can do to help the team work better together, and notices that yelling at Tony/punishments really doesn't work.

So he decides to try some positive reinforcement. Instead of telling Tony what he did wrong after a fight, he tells him good job, he's really helped, though it would be appreciated if Tony let the others know the change in plan next time. No one is more shocked at this turn of events than Tony, who has absolutely no idea of how to deal with it.

I'd like to see Tony slowly becoming a better team player, because he's never had that sort of approval before. No real need for minor references to Taming of the Shrew (or even better, Kiss Me Kate), but I would love you forever if you managed to work in the quote from the title. Especially if Steve is the one who mutters it where someone (not Tony) overhears, and then relays it to Tony who gets just a little offended that he's being compared to the Shrew.