Dunmer, for practically the same reason as Duncan Frost and the fact that they are a rascist bunch from top to bottom. However If they were a bit nicer people (like I hope they are outside their home province) I believe Imperials come second, their natural ability to believe they mean something more than anyone else makes me want to punch them all in their faces...
What's up with so many people disliking Bosmers? Yes, they were ugly as hell without Better Faces, but with it they looked really cute

. I also felt like they were the kindest race on Morrowind. So what if all males are slow-running gays? If they are nice to me I wont judge them.