I have nothing against genres and gameplay mechanics themselves, but the amount of them and/or their obnoxiousness makes me hate the very sight of them.
Sandboxes - They're fucking everywhere. I understand that linearity can sometimes be a tad restricting, but it has good features too, guys! It shows that the developers took time to carefully craft an experience instead of just dropping you onto a map and telling you to make your own fun! It also means I don't have to traverse the entire fucking Saharan desert every time I want to access an ATM.
First-person shooters - There are just too many of them, and not enough variation to make it reasonable. Surely there is a better way to convey your gameplay experience. Surely I don't have to spend the rest of my life with a gun lodged under my right eye. Surely.
Dialogue box RPG's - I'm sure that's not a genre that any reputable game journalist keeps, but it's going to become one at this rate. Way too many fucking games that are equal parts interaction and eerie, unmoving eye contact as you browse dialogue options like you're playing Windows Explorer: The Game. I understand that you feel this is a lot like human interaction and therefore adds personality to the game, but it's not, and it doesn't.
Any game with female characters dressed like they're in a shitty Japanese porno - Just stop it. It's weird.