4. Edward Norton
Throughout his career, Edward Norton has developed something of a reputation for being hard to work with, evidenced by how the director of American History X, Tony Kaye, wished to remove his own name from the (excellent) film due to Nortons taking over of the editing process, as well as how he was unceremoniously replaced by Mark Ruffalo in the role of the Incredible Hulk (who he played in 2008) for The Avengers. With greats like Fight Club on his filmography, however, few can deny the mans acting talents, which This Is The Ends creators Evan Goldberg and Seth Rogen sort to briefly utilise in their film. Though Norton was reportedly receptive to the idea, he was forced to say no due to scheduling conflicts, preventing the film from having an established method actor present alongside its assortment of comedic ones.