Rant on One-Dimensional Characters

In my editing adventures I’ve renewed acquaintance with my main bad guy. He is a bad guy who has done many bad things and thinks he’s awesome, and as I read back over everything I have been thinking ... but, what if he’s too evil? What if the only facet of his personality is his evilness, apart from his two-facedness? Do I need to make him more three-dimensional? Do I need to give him better, more understandable reasons for his evilness?

This way lies (further) further revisions and woe. But possibly a better story.

But is it really a better story? My character already has a few facets to his personality (I guess I’m selling him short by listing only two), and he has back story and everything. And in real life, people do terrible terrible things and other people don’t understand the reasons. Other people spend years studying and experimenting to try to understand the reasons, and still give up and say things like ‘well, it’s just like this.’

Real life often makes for unbelievable stories, though. So where is the happy medium between real-life one-dimensionalism and literary three-dimensionalism?

I guess the difference between a one-dimensional character in a story and an apparently one-dimensional person in real life is that, for the real life person, there really are other dimensions to them. They have an entire life history before they burst onto front pages of newspapers. Characters, however, only have the life history that we give them before they burst onto the front pages of novels. We must create the illusion of other dimensions, even if they are never mentioned, and this is difficult to do if your character’s actions only show one dimension. One-dimensional characters work as clichés and jokes, but not much more.

IMO, anyway.

ETA: Currently rewriting/editing scenes as if from Bad Guy’s point of view. Genius! I should do this for everything!