Matt Damon, Harvey Dent
Matt Damon immediately declined the role of Harvey Dent when he was approached by the producers of The Dark Knight. He ended up having a major scheduling conflict that prevented him from becoming one of the most legendary characters in movie history. When asked about leaving the movie behind, Damon said: “Look, Aaron is a great actor, so the movie didn’t suffer for it. Every now and then you get one and you can’t do it.”
Johnny Depp, Ferris Bueller’s Day Off
Johnny Depp was on the up-and-up in Hollywood in the 1980s. Because of his rising stardom, he was offered the role of Ferris Bueller in Ferris Bueller's Day Off. Depp turned down the role because of a scheduling conflict, but he has mentioned that he deeply regrets giving up the opportunity to Matthew Broderick.