Just got back from seeing the best movie of 2012 and there is something that is bugging me.

This may contain some spoilers. 

So, if you have seen it, I hope you’re still reading.

If you haven’t seen it and you’re still reading, this won’t ruin too much. And I will advise you see this movie.

Anyway, whilst upon the flying carrier ship after (possessed) Hawkeye starts shitting up people’s days, Black Widow is stuck and Bruce Banner is next to her. He starts to flip shit (figuratively and literally). But later in the movie, he tells someone (I forgot whom) that he is able to control his anger by staying angry and afterwards he is well in control of the Hulk and doesn’t attack any other of the Avengers.

I guess what I am asking is, how can this be?