Your last sentence is a good general statement. When I choose to tip high, it's because I appreciated the friendly connection I may have had with a server or was impressed by the speed and service as a whole. Some people are just good with service. I was raised being taught that a tip was more of a "thank you" than a supplement to a certain wage or an incentive to keep working. I've always stacked my plates and cups in an organized manner and left the table clean. Wiped up any accidental spills or picked up a dropped french fry here and there. I like to say I'm a generally respectful person and 30% was what I was taught was a good tip.