yes...we do it because it feels like the right thing to do and gives us a sense of doing that
hell that is a major tenet of being a decent human
The OP seems like a cheapskate. I like the tip system because it lets me reward good service. My wife and I routinely go out and either split on entree, or simply have an appetizer. I know this is a low bill for many waiters so I tip a higher percentage than normal. We are creatures of habit, and go back to the same places and are waited on by the same people. As a result, the waiters remember who we are, are always happy to see us and take great care of us... even pointing out when specials that we like are back on the menu.
Whether you agree with the system or not, that person is working for a living and taking care of you. Treating them well is simply the right thing to do.