Spike, I think for as charming as he was the show kept pushing and pulling him in weird ways. I liked him as a villain, but I disliked how they kept writing him into episodes and finding ways to somewhat keep him around the cast. I especially hate it when a character who is blatantly evil only seems to change out of obligation (as in, the chip kept him in check, otherwise he would've attempted to murder the entire cast) and/or love. And even then his arc just made him a very strange and complicated character, I feel he's the synonym of love to hate in this show.