WHAT is wrong with people?! Why are some people so selfish and only care about their wealth & their well being?

I live a very modest life regardless of the amount my husband and i make . We drive modest cars and dont care about big flashy things or name brand everything. I spend a good deal of money on other people who NEED it, and i try and help anyone i can IF i can. While i work for people who spend lavish amounts of money on ridiculous things. Like a pair of sungles from armani, that look JUST like the ones i bought at target. Or a plain white tank top from high end boutiques when again, i can buy that at target! It makes me want to just smack people! For that $100 tank top they bought, that they could of bought for $10 at target, they could of bought a family their groceries for the week! I just cant believe some people. Everything i do in my life, i look at "is it really necessary?, is there somewhere better this money could go?" Then people look DOWN ON ME, because i only have say 5 pairs of shoes versus their 100 pairs. Geez.