Why do some people care about fashion that much?

I never was able to understand it so maybe you guys have a clue? I mean, it's fine when you are wealthy enough not to care about money but when people don't even have savings and waste tons of money buying designer clothes, it's just really strange. I see a lot of women wearing designer clothes and Gucci handbags and I am one hundred percent sure that ninety percent of them can't actually afford it.