Well I'm not sure if it counts as I hate the bad guys and actually every single member of the cast but, that guy from Custom Robo on the GC, I have no idea what his name was but I named him Octopus, and he is such an idiot I was tempted to destroy the disc, but seriously the story of that game AAAAAAAAAAAGGGHH, it's awful.
I also didn't like Sheppard, none of the choices available made him likeable for me so I just went ahead and made him the biggest asshole possible, and then never played Mass Effect again, seriously I hate you Sheppard, I'm not even sure why but I do.
I'm pretty sure there's more as I hate way too many things, but I can only think of that for now, must be because I actually liked Custom Robo and the crew from ME so it hurts me more, but really real reason ME didn't work for me was because actually playing it was so boring, the cutscenes were the most entertaining part but since I hate Sheppard I wasn't going to sit through that.
[sub]Honorable mention, Hisao Nakai from Katawa Shoujo, because I don't actually hate him but he really, really pisses me off at times, like pretty much every sex scene, but really that's my fault for playing that thing knowing I don't do well with sex scenes in general.(They scare me more than any horror movie...)[/sub]