Villains and Halloween

I had someone ask me the other day why villains are so easy to write?  Personally I don't think they're always easy to write, but sometimes they sure are fun.  I think that writing villains is a little like dressing up for Halloween.  Halloween is fun because you can become someone else and walk in their shoes for a night.  You can put on a wig, use a phony accent, and just generally be a different person.  Not that you would want to be this person all the time, but for one night, it's wonderful to just pretend. 

Writing villains is like that.  We get to think about what a person making bad choices would do.  We get to be oh so bad on paper.  We can say things we would never say, we can purposely try to hurt people's feelings, and we can manipulate the world we are writing to be in the favor of the villain for most of the book.  It's not until the end that the villain gets his just desserts.  Another fun part of writing the villain is figuring out why they are the way they are.  If you write your villain correctly, he/she won't be evil for the sake of being evil.  There is a reason they are the way they are and you have to not only figure it out, but you have to allow the reader to feel a kind of sympathy for this person.  Even J.K. Rowling let you feel sorry for Voldemort, by giving him the same sympathetic situation as Harry Potter, he was an orphan.  In this, the reader feels a sadness for the choices of the villain and it humanizes him.  It lets the writer and the reader walk in his shoes, just like Halloween!
So what do you like about writing villains?