Chris Pratt will never not be adorable. That's probably the best reason Guardians of the Galaxy works so well. And I guarantee someone who sits behind a big mahogany* desk realized that, deciding to cast him in what would become likely the best movie of the summer. Sure the film has a bit of a head start, what with the movies that came out earlier cluttering that part of the brain reserved for long term memories. The only real contender against it would be its bookended Marvel counterpart Captain America: The Winter Soldier, but that came out in April so it doesn't count. Shut up, that's why.