As a game reviewer (and even before then), I always felt that to be a gamer you had to keep your options open. That said, there's only ONE genre I actively avoid, a few I'm not fond of, some that I'm picky with, and others I love but suck at.
AS for the games I avoid, It's only sports games. Ended up volunteering to do MLB 12 The Show on Vita a few months back, spent more than 12 hours on it and could NOT figure it out. There were numbers everywhere I didn't understand, a character creator that was VERY detailed but all the stats and info was above my head, and I just had no clue what the fuck I was doing. I fear it'd be the same for any other game in the genre, too. Without a comprehensive "how to play" manual or explanation of what all the stats and info meant, I'm completely lost. Plus like many others, I'd rather play the for real than play a game of it or watch it on TV. Not that I think I should apply that logic to others (I hate the "don't play that genre, do it for real" Card after the debacle that was the Guitar Hero/Rock Band players vs every other ignorant 'tard in the world deal)
Not really interested in racing games unless it's gimmicky or combat racing.
I enjoy puzzle games but I tend to do poorly at them because I don't have the patience to do the same thing over and over again.
I love Strategy RPG's, but I kind of suck at them. Final Fantasy Tactics kicked my ass.
I enjoy Real Time Strategy, but again I kind of suck at them.
I'm not particularly fond of MMORPG's, mostly because I don't like the idea of a monthly subscription. that, and the gameplay is shallow "clickclickclick". I suppose this would qualify as another genre I avoid.
I'm picky with my fighting games. Stuff like Smash Brothers is awesome, and I'm quite fond of the Soul Calibur series, but I don't like tekken, for example.
I'm kind of neutral-to-negative on FPS games. I love shooting t hings, but when you've been playing them enough, they really blend together. Stagnant is a word to describe the genre, something like Borderlands is awesome.
I can't think of any others.
My Console Library:
PS5, Switch, XSX
PS4, PS3, PS2, PS1, WiiU, Wii, GCN, N64 SNES, XBO, 360
3DS, DS, GBA, Vita, PSP, Android