I can't believe that is your opinion.
While my wife has not had breast augmentation surgery, I have known a few members who have. The few that I have spoken to get it to feel good about themselves, to restore something that was lost in having children. They aren't getting it so they have huge beach balls for everyone to look at. They aren't getting them to keep up with the neighbor across the street who did.
If you had your face torn up in an accident would you try and get it fixed through surgery? I sure would. I don't think that makes me vain as much as wanting to be me at my best. Women who lose certain aspects of themselves can get depressed and if all it takes is a surgery to make them feel better why in the heck not?