The Marvel Cinematic Universe actors are just as cool in real life as they are on screen. In fact, the actors even seem to be friends when the camera's aren't rolling. They tweet each other, troll each other, and apparently kiss each other when the opportunity arises.
Just follow Robert Downey Jr.'s Twitter account if you need to see the Avengers cast in action between MCU movie releases; he posts all the best tweets and seems to engage everyone in a bit of light ribbing. Who wouldn't want to be a part of the Avengers in-crowd?