Might I recommend these TVTropes pages:
The Sociopath
Serial Killer
Freudian Excuse
Within all of those there is certainly room for money, power, and women to be motivators for horrible things, as well as for relatability with horrible people. The Joker is only one variant of horrible person, and he falls under Complete Monster. Not every villain is a complete monster. Many are not. Look at most of Batman's villain pantheon. A lot of them have triggering events that made them the way they are and direct their motives in relatable ways. Maybe not sympathetic ways, but understandable ones nonetheless. And some of them use sex, Poison Ivy coming to mind.
I currently play a villain who would rather chop her own head off than have sex. I have also played a villain who was much more the sort to be found in the Quicksand. Que sera.
The Sociopath
Serial Killer
Freudian Excuse
Within all of those there is certainly room for money, power, and women to be motivators for horrible things, as well as for relatability with horrible people. The Joker is only one variant of horrible person, and he falls under Complete Monster. Not every villain is a complete monster. Many are not. Look at most of Batman's villain pantheon. A lot of them have triggering events that made them the way they are and direct their motives in relatable ways. Maybe not sympathetic ways, but understandable ones nonetheless. And some of them use sex, Poison Ivy coming to mind.
I currently play a villain who would rather chop her own head off than have sex. I have also played a villain who was much more the sort to be found in the Quicksand. Que sera.