Personally for me, I hate the following.
1. People who clown around too much, especially in serious situations.
2. People asking me what’s my class and abilities in game. ( learn what I am and what I do in game....that is, if I so choose to show or tell you, either way, let’s role play it out )...
Hummm....this is tougher than listing the 10 worst. I had plenty of "BAD" rpgs to choose from. Oh well. My top ten....
10) Cyberpunk Version2
9) DC Heroes 3rd Edition
8) Big Eyes Small Mouth 2nd Edition
7) All Flesh Must Be Eaten
5) Fantasy Hero
2) Delta Green...