Why do white women put lots of make-up when they are naturally pretty?

So I am an Egyptian dude, almost 17, now I am living in the US (lived in Russia and England, and studied in China during college before) and I work as an aeronautics engineer. I was born in Christian but currently Atheist or just Agnostic. Anyways so my girlfriend is white, she has naturally blonde hair, blue eyes, average body and she's really pretty without make up (not saying this cause she’s my girlfriend) but like many or maybe most white women she likes to put make up and thinks she will look prettier with it even though I told her she's already pretty without any at all. I of course don’t mind it, I like her both ways I know its funny but she kinda looks fake with it like a Barbie doll. A lot of white women look naturally pretty. Why do they put that much make up?