I'd actually hesitate before laughing at people who don't feel secure in their own skin. It's easy to mock people who aren't attractive, or who don't feel attractive, when you do feel attractive, but think about it--isn't a measly $4k a really good investment if it increases your self-esteem, makes people treat you better, and improves your romantic prospects?
Myself, I'm probably going to get Lasik very soon since I have piss poor vision, and I will not hesitate to spend the $5k or whatever it costs on it. The convenience, security, safety, improved job prospects, increased physical health, and other benefits make it a worthwhile investment.
The same may well be true for many women who are interested in getting breast implants.
It's of course no replacement for a lack of exercise or an undisciplined lifestyle, but what is the purpose of money and technology if not to dramatically increase the quality of your life in the long run? And I don't think anyone could seriously argue that breast implants, for some women, may amount to a dramatic quality of life increase.