So there is a lot of generalization about tipping - Men are better tippers than women, teenagers and foreigners are the worst, etc etc. I wonder if there is any consistency with tipping across types. A friend of mine compared my bad tipping habits with ISTJ's trait of being poor at giving praise.
I dislike that there is an obligation to tip (in the US at least). A tip should be for performing above/beyond expectations. However, I also think it should be illegal to pay servers below minimum wage. I generally try to tip around 10-15% if they haven't screwed up. But I remain annoyed that they get away with paying servers less than minimum wage.