Since my freshman year of college, I have worked in a restaurant non-stop, first as a host for eight months and then as a server at a different restaurant.

At both jobs I was paid a sub-minimum wage and was considered a tipped worker, which meant that almost all of my paycheck came directly from the tips that customers left at the end of their meal.

Knowing that my paycheck comes from customers, it baffles me that people still walk into a restaurant, use all of the services provided and neglect to leave a tip.

I could list off reasons that patrons should leave a tip all day, but here are some important ones.

The main and most important reason you should tip your server is because tipping, while not required, is not actually optional. The federal sub-minimum wage for tipped workers is only $2.13 an hour, a number that has been the same since 1991.

The rest of the money that servers are paid comes from the customers. When you walk out of a restaurant without leaving a tip, you just made that person work for free and then some. It is 2017, and people still don’t know this.

Another aspect of serving that people are surprised to hear is that servers do not receive all of the tips that customers leave. A percentage of the money that customers leave goes to the server, and then, at the end of the night, the servers tip out to other employees such as the hosts, bartenders and bussers. This, while a little misleading, makes sense. From the moment someone walks into the restaurant, you are using the service of the people who seat you, make your drinks and clean up after you when you leave.

Finally, serving is hard physically and mentally. Servers spend hours on end walking constantly. They lift heavy boxes and trays of food. And not to mention the mental hardships. Imagine every interaction you have with a customer being directly linked to whether or not you pay your electric bill on time. It’s stressful to try to please a total stranger

According to the Bureau of Labor Statistics, an estimated 2.5 million people were employed as severs in the U.S. in 2015. Of course, not every server’s experience is the same as mine. Some restaurants tack on a mandatory tip amount as part of the charge.

California requires servers to be paid a minimum wage while allowing tips on top of that. But most servers have a situation similar to mine, especially around here. So show some compassion to someone who’s just trying to live their life. Tip your waitress.