Our widespread system of gratuities and taxes on tips wasn't always this way. Historians write that in early America, like before the Civil War, tipping was frowned upon because it was seen as classist. If you tipped someone, it meant you thought of them as beneath you.
But when wealthy Americans went abroad, they brought back the practice of tipping that Europe had at the time. After the 15th Amendment did away with slavery, some restaurants used tipping as a way to keep wages down, and well, here we are today.
While this was all happening, the American anti-tipping attitude crossed the ocean and was adopted by groups advocating for workers' rights in Europe. Today, most restaurants in Europe might look at you funny if you leave a tip.
But using tips to function as minimum wage has been allowed since it was codified by law in 1939. That means delivery drivers, hair stylists, bartenders, dog groomers and freelancers
working hundreds of other jobs in the US make a significant part of their income from tips. And as with most other sources of income, the IRS asks for a share.