Todd Wallinger at 2011-02-02 16:33:05:
Scott Neustadter wrote a screenplay about a lousy relationship he had and turned it into (500) Days of Summer. It all depends on what you do with it.
The best part of the story is that after he finished the screenplay, he gave it to the woman who had treated him so shabbily to see what she thought of it. She loved it. Turns out she saw herself as the Tom character.