The nerds at school that give all gamers a bad name, every lunch/recess they'll go to a computer room and play video games, and completely ignore the only good part of school - being social. Also this means that I can't admit that I'm a gamer without sacrificing a part of my social life, or that I like particular games that they obsess with (eg. Oblivion, minecraft). These are some of my favourite games, and very good games, but the only games I can admit to playing are COD, Halo and FIFA.
This is why I never tell the norms that I play videogames. Then again the firearms stuff tends to polarize them anyway...