Why do you think people leave tips at restaurants?
Not interested in discussing HOW MUCH you tip, just WHY.
Put another way, what compels a person to tip, no matter how much or little?
It certainly isn't the law, such that it would be illegal not to tip (generally speaking, of course).
Is it for the "service" of the server? But the server is already being paid a wage for being there (no matter how little, the server is being paid).
Is it something about social mores and perhaps even peer pressure? If it is, what about when you are dining alone at a place that you will never return to? If you left no tip, who would know? Yet, we still tip (at least I hope we do).
Is it something that makes us feel "good" or "better" about ourselves? In the same way when we donate food to a food bank or shelter?
Is it just a force of habit? Something that is just expected?
Is it just the "right" thing to do? If you say "yes" then it just begs the question. Why is it the "right" thing to do?
I mean, seriously, at what other time do we simply "give away" money to non-family members without there being some sort of religious undertone (tithing), moral principle (donations to the needy), or otherwise compelled by law or contract?