I can't think of a character that I outright hate, at least reading wise. There's characters who at first bugged me, like Steris and Shallan. They always grow on me though, especially Steris. There's also characters that I might dislike for what they do like Moash, but he's still a compelling character and entertaining to read. It's why I love Brandon's writing, his characters are always compelling, even if you're suppose to dislike them.