Like to look pretty? Capitalism has somehow convinced you one clear rock is vastly superior to another, identical looking, cheaper clear rock. I challenge you to find me someone who can tell the difference at the distance anyone seeing you wear them would see it.
Capitalism, as well as racism - throw that in for good measure here, has convinced you to add a little fee to your meal so the restaurant can pay the staff even less than poverty wages!
Yes, tipping started with making sure black people got paid less since they couldn't legally have slaves now. Well, at least not blatant obvious slaves.