Whedon's a famously loquacious guy, so it's always worth hearing him talk about damn near anything, but particularly how he plays characters off one another here.  Most importantly, how he ensured that these superheroes were battling for compelling reasons, with contrasting legitimate motives rather than an arbitrary excuse to put them in a fight.

Plus, his thoughts on the headbutt are just spot on.  Watch and listen in this clip, courtesy of Yahoo! Movies.

Oh, Joss, you speak the language of my heart, and your words are music to ears of nerds the world over.  Whedon's making his sophomore directorial feature here, and if anybody's somehow still worried it's an impossible leap from the low-fi sci fi of Serenity to the large scale super-shenanigans of The Avengers, then I'll simply quote Attack the Block's Pest and say, "Believe, bruv."

Yeah, Iron Man and Thor toss each other around to great effect, but there's also the conflicting styles of Robert Downey Jr.'s rapid-fire delivery and Chris Hemsworth's godly grandiosity.  Somehow, though, they work in the same universe, as do Chris Evans, Mark Ruffalo, Jeremy Renner, Scarlett Johansson, Samuel L. Jackson, Tom Hiddleston, Clark Gregg, and Cobie Smulders.

The Avengers assembles this Friday, May 4th.