I would wager that a lot of the worst people don't even consider their position in their own story. They're the centre of it, anything else is an afterthought.

The pattern I see repeated is people do what they think is best for themselves, if that benefits others or not is inconsequential. Sometimes what's beneficial to you is giving someone some money to make them trust you, sometimes it's stealing money from their pocket and convincing then otherwise. Being a "villain" is irrelevant to the overall goal.