I personally couldn't stand Alistair from Dragon Age. Not so much as a friend or partner, but he was an annoying love interest. Same with Tidus, really.
Also Alucard from Helsing
The dude can't die. It's like learning a magic trick once you know how it works, it loses it's luster. He's been shot, decapitated, reduced to a puddle of blood, and just reforms, says some spell, and goes berserk. I like my heroes and anti-heroes to struggle, and if they aren't in mortal peril, then it gets boring.
It's like watching Superman.
Needless to say, I don't hate these characters, they just either annoy me or don't appeal to me.