If you can't accept your looks as is, you have low confidence in yourself. :/
But reconstructive surgery is alright. I mean, some people get messed up by things and don't want to go around with half a face. That's understandable.
There are some people who really do need it (and not because they think they're ugly, people who need it because that certain flaw is giving them problems, or something like that), but all in all, I don't think plastic surgery is really necessary. Because, number 1, it's like saying you're not enough for yourself, it's like putting yourself down, number 2, it hurts, number 3, it's expensive. :/
Really, who needs plastic surgery when you've got cosmetics? :D