Thor and The Hulk/Bruce
I feel like Iron Man and Captain America are like the cool kids who are always full of drama. And Thor and the Hulk/Bruce are the geeks who are completely out of touch with the drama and just hang out at each others houses playing with chemistry sets, video games, and D&D.
Playing with chemistry set:
Bruce: Thor no! Don’t pour that into…!
Thor: Oops… Haha I’m sorry, but you look really funny without eyebrows.