Well...
1. Racists
2. Girls who flirt with you and then it turns out their lesbians (one time, don't ask)
3. Feminists
4. [Hostile]
5. Attention whores
6. Noobs who don't post in the welcome wagon
7. People who thing they are much better than everyone else.
8. Doctors (again, don't ask)
9. Ex...