Allow me to once again make status.
It seems to me that most actors playing evil say they will always try to defend their character no matter what horrible acts he or she commits, because that makes the character less one-dimensional and more interesting. But I've noticed that many of you feel they have to defend not only your character but evil itself which is quite different. This is not to encourage a philosophical discussion, just makes me wonder.
Others answer they want to play evil for fun or to let out their inner demon or devil (my words not yours) which I can much better relate to.
Some want power beyond what a good alignment can provide. Others just find evil characters to be more interesting.
I now realize that my original post and question entice many of you to explain your ideas about what it means to be good or evil. Please focus on answering the original question and if you feel you have to elaborate on it by describing your views on good and evil I guess that is ok.