No actor can play a villain if they don't sympathise with him or her - otherwise the character just becomes a two-dimensional caricature.
Every villain in the DC Universe wants something different, and not all of them want to rule the world. Or at least, not all of them want to rule the world in the way the Crime Syndicate do.
I define 'social thriller' as thriller/horror movies where the ultimate villain is society.
I've never really been serious about my villainy. I don't have a master plan. I suppose my philosophy is: Every villain has a mother. For every cold-blooded killer on your screen, there's a little old lady somewhere who calls him 'sonny.'
I think 'Voldemort' is definitely the scariest villain.