Pop Gaf and Brony Gaf creep me out a little bit (a lot actually).
Anime Gaf is actually very friendly, and have done a good job of recommending good anime, but I feel like the standard answer when asking for a rec is "Cowboy Bebop". I'm like, c'mon, is there anyone on the plantet that watches anime and hasn't seen Cowboy Bebop?
Trans Gaf is super agressive (I can sorta understand why though), and seem only to be interested in the sociological concept of gender.
HipHop Gaf has too many Eminem fans. I mean, he's ok, his lyrics are alright if you like trainwreck sort of things, but his beats and production are standard for mainstream rap music. He also gets recommended at inappropriate times. I remember a thread where someone was asking for early rap artists, and everyone kept recommending Eminem and Golden Age (even though OP specifically said he wasn't looking for Golden Age).
Israel Defense Force Gaf is an absolute riot. Israel-themed threads are at the same time mind-boggling and hilarious.