I struggle to enjoy:
RTS - ... I just don't like them...
2D Fighters - ... I just don't like them...
Sports - It's always the same shit year after year... I once had an NCAA game that I enjoyed. Also used to like NBA street Volume 2. That's pretty much it. Other than those 2 experiences, I just don't like sports games.
MMO - I don't hate this genre. I just can't find one to really get into. There were a few I tried and liked but I just lost interest quickly.
Singing Games - Not Music based games in general... just the ones that require me to sing. I don't sing. What? You wanna fight about?
That's all I can think of right now.
4 ≈ One