What makes a good villain? Why does the antagonist have to be a one-dimensional cardboard cutout consigned to evil for the sake of being evil? Can we actually delve into the character’s understanding and find out what makes their mind tick?
The harbingers of change that skulk through the dirt and fugue trying to make the world a little brighter are often the best (or worse?) villains. Good villains have believable rationalizations and thoughts. They don’t go around god-hammering innocent kittens for the sake of doing it, they do it because making kitten milkshakes adds to their power or furthers their agenda, not because they were walking along and go “Oh hay, a kitten!” *THUUMMP*. Regardless of the term, good and evil, rude and kind, etc, the same principles apply. What makes a villain believable is that we can understand and rationalize their actions and thoughts. We don’t have to like them or even agree with them, but understanding why they do what they do when they do what they do really tightens the story like a moose’s bunghole during fly season.
My personal favorite brand of tyrannical douchebaggery is when the villain is calculating and logical, and tries to solve some problem that anybody with a heart bigger than the Grinch’s will throw the bullshit flag on. Some examples would be Ozymandias or AI (I,Robot) so set on protecting humans from themselves, they must trick and/or oppress and dictate every decision. Characters who plans are so methodical and well thought out, we see the protagonist playing into their every move. To me these make the best villains. Case in point: Joker from The Dark Knight, boom. A great villain forces heroes to make hard decisions, and if the hero is worth a damn, will make those decisions so nobody else has to.
We love to hate villains, and the more we like them the more we resent the fact that we like them, even if for a second we break the narrative and find ourselves agreeing with them. When their moral compasses not only point over to the grey stormy areas, but also show some sunshine below the Mason-Dixon line where you can’t help but connect. In my opinion those are the best bad guys.