@ the villain question: I think it depends on which part of the "love to hate" you want the audience to focus on--if you want them to really despise the character, or if you want them to sympathize with them, so to speak. For example, Umbridge vs. Marvel's Loki. Umbridge is almost sadistic in her treatment of those who oppose her and is very unpleasant. With Loki we're shown reasons behind his actions so while we understand he's the villain, we don't outright hate him as with Umbridge.
I’m loving all of these answers! They’re so diverse!