Genre I hate the most would be, Simulators games, the majority of sports games, and puzzle games like Myst that requires you to use 90% of your brain (I can handle games like Tetris and Bust A Move, but not superthinking games).
Other then that, many genres I used to hate, now, at least tolerate and maybe even like now (i.e. FPS, RPGs, Survival Horror [or horror games in general]).