I've learned this is a really complex issue, Anthony. Makeup and heels always made me nervous because I still looked like me (that is, not a natural beauty; "plain" probably hits the mark), only like a badly made up Cubist painting or something. So I didn't bother because it made me feel uncomfortable rather than pretty.
But in conversing with a lot of women, I have really found that they use make-up almost as self-esteem boosts or armor--they really feel better for themselves using it, and it often has nothing to do with men.