The system of tipping servers in the United States is terrible. It’s glaringly, obviously, bad.
Servers are employees, and should be compensated like any employee, with an hourly or annual rate. There’s no reason to add randomness into the equation. We don’t tip cashiers or janitors.
It’s possible that the tipping system might encourage servers to work harder, but the reality is, most of the important factors are not in their control. They can’t control how fast food is prepared, how it tastes, how long guests had to wait for a table, the noise, or the price. The only thing they can control is their own friendliness and bringing the food to the right person. Some people are generous tippers. Some don’t tip at all. Why should the employee take that risk? It should be the business owner who takes the risk. That’s the whole point of being a business owner.
It creates an unnecessarily complicated tax situation wherein the employer has to pay a minimum wage, but then more if the server didn’t make enough from tips. It creates awkward situations. We feel bad for hard working Americans and tip out of donation, instead of merit. If the business really wanted improved performance, they can pay commission to servers who serve the most people, or order the most alcohol. Ultimately it creates worse quality because servers either resign themselves to the randomness of tips, or leave the restaurant industry for jobs where their efforts are consistently rewarded.