change their tips based on observable, quantifiable variances in service. Basically, most people, most of the time don't change our tips for quality of service. This is one of those classic Coke vs Pepsi taste test scenarios. folks are convinced they are the exception to the rule, blind studies show differently.

But what matters is the servers think their service matters , so they strive for better service for better tips.

There are some things servers can quantifiable do to increase tips. One is leaving candy with the bill.