I love the implication from Team Thor that Tony tried multiple times to convince Bruce to be a part of Civil War (”How many times do we have to go over this?”) 

Surely it started with an appeal to their special bond: “Bruce, Science Bro™, please, think of all we shared. Think of our murderbot son! Well no, maybe don’t think of him, but good times were had, Bruce, we both know it” 

But it seems that somewhere along the way this devolved into “Goddammit Bruce! I will fucking give you MONEY to bring the Hulk out here and smash everyone on Team Cap, come the fuck on now!” 

I just assume Bruce tells him at some point “Listen! T-Bone, I love you, you know, but if you come at me about this again, the Hulk will come out and your metal ass will be the first to die.” 

But Tony is so persistent that Bruce finally hitches a ride with Thor and flees into space, apparently. Truly the most realistic depiction of friendship in the MCU.