The bad guys I've known were could be very charming when it mattered or to the right people. It took several months (sometimes a year) for people to compare notes and realize they were basically jerks. One of the nicest guys I've ever met I later found out verbally abused (and sometimes physically abused) his wife, often stole money from her purse to go get high, left his kids in a seedy part of town because he was too high to remember where they were, and spread many horrible, demonstrably false rumors when they separated. Maybe some of the people you helped because you thought they were nice, many years from now, you will realized they are sociopaths.

I think they may just be a lot better at framing the options for the people they manipulate in favor of their desired outcome. Mostly out of necessity, because people really don't often like helping or working for jerks. The most successful bad boys include a factor through which it is also beneficial to the people they are playing or even better - a factor through which they think they are the ones pulling ahead aggressively.