"That's because he's Tony Stark and he isn't used to people telling him no." Bruce tried not to smile, he really did. "You should try it sometime. It's actually interesting to watch his face as he tries to figure out why you told him no. I'm sure it'll be even better when there isn't a real reason and he'll spend all day trying to figure it out."
Jokes were good. Jokes on Tony were distractions from the previous subject. Bruce could do that, could handle subjects that didn't involve him.