Everyone enjoys a good villain in a story, especially if he/she is a well-written one. Villains cause havoc, do unspeakable horror to other people, and are rarely bothered by their conscience. What makes them intriguing is how a mind of a villain works. Their unpredictability and ruthlessness makes them a ticking time bomb waiting to explode, and standing back to wait for it to happen is what leaves you seduced by them.
A villain who is plain evil without a motive or a back story explaining why they are who they are makes the character forgettable and inaccessible. Once justice is dealt on the villain it just becomes a case of, “Well, he/she had it coming. Good prevails over evil. The end.” If you are like most people, you want your villain characters to be multi-faceted and not one-dimensional. I can think of the Disney villains as being one-dimensional for the most part. They are fun to watch and only serve the purpose of being the foil to the hero/heroine until their comeuppance happens at the end.