Hair Cuts at Great Clips (or where ever) do you tip?

I tip but don't see the point. They don't do much work at all then you pay them then turn around and pay them again. I work at a feed store and load people up with feed and hay all day long. Once every month or two if I am lucky some one will hand me a few bucks. I will load up 20 bales in some ones truck, thats 100lb bales so a ton and they just drive off. Not that I expect it or think they should either. Just find it strange some one who goes snip snip a few times should. But like I said I do tip because thats what your suposed to do.