I have a few. Laine Kimble from
No Man's Land fits that very well, though although my readers are only wary of her right now, they will most definitely begin to hate her as she comes into the story more. Personally, I just feel sorry for her. She wants back into the life of Jackie Flores; she actually does miss him, maybe even still loves him, but she made a mistake and was forced to suffer for it when he broke up with her because of it. Now, if she ever gets the chance to get close to him again, she'll just come off as rather possessive...not to mention neurotic.
Jackie Flores isn't always that likeable either, though. He comes off as a fairly decent person in the story
now, but a one-shot I'm writing about him right now portrays him as just the worst sort of asshole. But then, we all have that tendency when thrust into particularly unpleasant situations.
Thing is, I rarely see unlovable characters that I found to be all that believable. They remind me of most Disney villains. They're bad, there isn't always a reason explaining
why they are this way, and it's fairly obvious that they only exist so the reader has
someone to hate while they're reading.