If you want to understand why Edward Norton and Marvel parted ways, you've got to know a bit about the key players involved. Because while Norton is a talented actor and Marvel produces some amazing films, both the man and the movie studio can be pretty difficult when it comes to getting their way.

It's widely known that Norton is a guy who likes to call the shots, even when he's not the one in charge. While filming the Hannibal Lecter thriller Red Dragon, he decided on his own that the screenplay wasn't good enough, so he showed up on set one day with lines he'd written for himself... and Anthony Hopkins. When he refused to star in the remake of The Italian Job — a film he was contractually obligated to do — Paramount had to threaten a lawsuit before he accepted the role. And perhaps most infamously, he used his A-list clout to re-edit American History X, a move that infuriated director Tony Kaye.

Of course, Marvel Studios has had its fair share of "control freak" moments. Under producer Kevin Feige, the company has clashed with a couple of directors who wanted to break free from the house style. For example, when execs didn't like Edgar Wright's vision for Ant-Man or Patty Jenkins' take on Thor: The Dark World, they said adios to those auteurs. The studio also gave Joss Whedon a hard time during Avengers: Age of Ultron, and the filmmaker had to fight tooth and nail to keep certain scenes in the movie. As for actors, Terrence Howard was kicked out of the Iron Man series after allegedly being lowballed by the studio.

In other words, Edward Norton is an immovable object, and Marvel Studios is an unstoppable force, so when the two crashed into each other, things got really messy really fast.