This is because the restaurant business is about hospitality and service, yet when servers do not get paid for their services, they are expected to grin and bear it. Imagine standing on your feet for six to eight straight hours, running back and forth between your tables and the kitchen and getting paid only half the minimum wage, counting on tips to bring your pay up to minimum wage level. That is what servers feel like every time they receive a tip that is 10 percent or less. Tips are basically a server's only income. Yet some of us do not have parents sending blank checks every month or collect a Pell grant.
Some people have to take what they can get and make the best of it.
Here is a solution I think most diners should use when dining out. Come in with a good attitude and try to put aside your troubles. Start with a 20 percent quota for a tip. Come into the establishment willing to tip 20 percent of the bill, but also willing to deduct percentages for a lack of good service. Say the server took too long to greet you that is minus one percent.