Marvel has brought together an amazing set of leading men for their Avengers Universe. From established vets like Robert Downey Jr to virtual unknowns like Chris Hemsworth, the casting has been impeccable. Plus each and every one of them looks like they're having a great time.
If you wanna know why you have so much fun watching those movies, it's because they're having so much fun making them. Here's the GIFs to prove it.