MCU: 14 Things You Learn Rewatching The Avengers
6. "I'm Always Angry" Was Better Than "I'm A Repressed Loner"
Though there is something to be said about the emotional repression of the first two actors who played the Hulk in modern Marvel movies, they're nothing compared to how good Mark Ruffalo is. And it's chiefly because of the different way he plays with the character's emotions.
Ruffalo's Banner is a man in control who is haunted by what he could become IF he lost control, rather than a man living on the knife edge of losing control. It's a subtle change, but it's the key evolution that made him a success.
There's more life to this Banner, more self-awareness and the crowning gloru of his "secret" that he's "always angry" is just wonderful. It also sets up Banner's entire arc for the MCU that is still unravelling into Infinity War.
Also, the first Hulk out scene is incredibly well done and the Hulk/Thor fight is great fun.