Things that should never be in fan fiction:

1. Mary Sues - use the characters found in the anime. That's what they're for.

2. Several thousand flashbacks - it works for the anime but not for fan fiction.

3. Polls - fan fiction is not a popularity contest.

4. Mary Sues - stop making up new characters because you hate the canon ones. Get out of the fandom if you hate them that much!

5. Author's Notes that are longer than the contents of the chapter. 'Nuff said.

6. Mary Sues - however cool you may think your new character is, she's still lame.

7. Character bashing - it's immature and dumb. So what if Sakura is a Sasuke fangirl. Ino is too so why don't you go bash her? You just get to see Sakura fangirling a lot because they're on the same team.

8. Original Female Characters a.k.a. OFC a.k.a. OC a.k.a. Mary Sue a.k.a. stupid excuse for a little fangirl to insert herself in fanfiction so she can pair up with her favorite character.

9. The author explaining whose point of view I'm reading from. Pick one: third person, first person - and stick with it. When you change point of views, don't label them. The readers are not stupid. Just tell the bloody story without specifying which character we're reading from. If you can't even write fanfiction without doing that, then stop writing and go read a book.

10. Mary Sues - they shouldn't even exist. Die Mary Sue, die.

11. Harry Potter crossovers - Why do people think they can combine everything with Harry Potter? What is the purpose of mixing ninjas and wizards together? If you "invite" Seigaku to play an "invitational game" at Hogwarts, the players who have difficulty speaking English will make good target practice for the Death Eaters. Does Hogwarts even have a tennis court?

12. Mary Sues. Itachi killed everyone in his clan. Period. Fangirls who write about one other Uchiha girl surviving and leaving the village to grow up in the Hidden Village of the Fairy Dust deserve to be dipped in molten hot lava.