Okay, I am a little, but still you get the point.
One of the best examples of fan fiction done wrong is "Doom: Repercussions of Evil". It is famous on some internet circles for just being horrendous. Here's an article discussing it with the fan-fic in its entirety (it's really short). You can see why it has a horrible reputation.
One of my favorite websites to visit, ScrewAttack, has done the fan fic justice with a little movie promo. I wanted to share it all with you guys. It's hilarious, and probably better written than half the movies that will come out this year.
Okay, I'm joking, only a quarter.