Why do people care so much about money?

I don’t understand why people have to be gloating about how much they spent “on this” or “that”. I hear so much of this at my school and it just makes me so upset because I think about all those other kids who’s parents probably make just about minimum wage and can’t afford anything that expensive.. Like it makes me so angry. But I honestly can say that to those people who think that the best things in life is having money, and you know who you are, this world we live in is only temporary so that money and expensive things you have, is temporary and won’t mean a thing when you leave this earth. I mean like really, try doing something meaningful with your life!!!