To each her own. I personally would never spend a fortune on a pair of jeans, but I will admit to having paid quite a bit for "the perfect dress" or a great pair of shoes. Jewelry...I love it, but don't wear it nearly as much as I used to, so now I just buy new pieces when I have an event to wear them to. Makeup...if you want quality stuff that won't make you break out in hives, you gotta pay for it (I have extremely sensitive skin, so only certain brands of makeup work for me). I wouldn't call it a waste; if you can afford to do it (and still pay the bills), and it makes you happy, go for it. But there is a certain joy in finding all the things you want at half-price!
Companies know that women will pay more for things they want, and price items that way. It's also a status thing; some people judge their worth as human beings by how much they spend on nonessentials.