I don't like the over-addicted MMORPGers who either lose all sense of reality, or later try to exult themselves saying how long they played, and how awesome they got.
Also, I really despise it when a really high level, skilled players go up to someone who just got started(a n00b, to be precise) and just start killing him because they "pWn all n00bz lolz". These people probably aren't even good enough to fight other players their level, so they take it out on newcomers.
I don't like anime that put needless moments of fanservice in them. I mean, if it seriously detracts from a serious plot, and doesn't really give good comic relief to make up for it, it feels too cliche and overused. And of course, people rave over it, and I find them sad.
I've never really liked table top RPGs, mostly because I think the setup takes WAY TOO LONG, and also because I have terrible luck rolling dice. Like, rolling three 1s on a D20 in a row, bad luck.
I may get crap for saying this, but despite its complexity, I don't like Magic the Gathering. I'm not much for card games anymore and I understand several can be amusing, but I find the unending popularity of Magic to be astounding. Maybe its because of my newfound frustration with so many American RPGs revolving solely around fantasy, Warcraft/Lord of the Rings style, but I'm really tired of seeing so many people at school with mountains of Magic cards.
And I don't like all the Space Marine stuff that populating America's sci-fi gameplay market when its not being overrun by fantastical Warcraft/Lord of the Rings style RPGs.
I guess ever since I started critiquing movies, anime, and games, I've come to be a bit more despondent at somewhat "geeky" trends such as these. Despite the fact that I consider myself to be geeky, I try to avoid things that become trends because most trends eventually boil down bland stereotypical versions of the originals that made them interesting in the first place.