I always tip for personal services like massages, tattoos, haircuts, and pedicures. I figure the price is for an adequate looking/feeling service and it it looks or feels good then a tip is a way of showing them that you appreciate the fact that they didn't flinch when they had to touch your nasty body. I also tip serving staff because our wage system is specifically designed so that they depend on them. I do NOT, however, put money in those ubiquitous tip jars that seem to be popping up every time you go anywhere. Other than those listed above, nobody who makes over minimum wage needs a tip just for doing their job.