I'm really not a fan of the "good guys are beautiful; bad guy are ugly" trope.

I feel like a villain is more dangerous if he or she is appealing in every way. And, to be quite honest, looks matter. They're the first thing you see about a person and people make snap judgments based on them. A guy who's all scraggly and scarred and hunched over and looks like he's two seconds away from shanking you really isn't gonna incite feelings of trust. Someone who you're attracted to and who looks like your everyday nice person though...they're dangerous cuz you'll never see it coming.