I went out with a girl who had been my best friend for like 2 years. Amazing, right? Wrong. After about a year and a half, she breaks up with me because she wanted to go see Bronson at the cinema whereas I wanted to go see Monsters Vs Aliens. She claimed I was too immature... yeah, really.
Then we got back together and broke up a second time about three months later (that time wasn't ridiculous or interesting).