Question: In the climatic battle of [**The Avengers**](http://www.imdb.com/title/tt0848228/), we see the full might of our heroes teaming up to protect the world. 

However, [**one scene**](http://24.media.tumblr.com/03d89ab3fe7b118238963319b30994e8/tumblr_mmswbjHqd41r1mr1po1_500.gif) during this battle, while hilarious on it's own right, does not make much sense to me.

While battling the Chitauri together, Thor and Hulk eliminate what appears to be a small force residing in a building. While catching their breath, Hulk all of a sudden *punches Thor with great force away from him*. 

But **why** does he do this?

The theories swirling in my head point to either a *revenge* punch for their fight in the Helicarrier. Or a *brofist* for beating a pack of Chitauri, taken a bit too far.

Is there any official wording on why this happened and Thor seemed to think *nothing* of it?

Answer: 
Although I have nothing to back this up, I am a writer and one of my characters parallels the Hulk fairly closely. In my mind, there's little doubt why he did it. He loves to hit things, he just got through having an aggressive fight, Thor is still upright, and he knows that Thor won't be hurt by it. It's like punching your teammate on the shoulder pads after he makes the game-winning touchdown, only sized up to Superhero proportion.
It was obviously a case of Hulk having the last laugh, so to speak and was intended to make people smile or laugh.

I highly doubt that there is any "official" reasoning available for such a minor thing which is clearly intended for the viewers to make what they will of it, with the implication that it was in relation to their (Hulk & Thor's) earlier battle with one another.