Why does one tip a waiter/waitress, hair dresser, masseur/masseuse, cab driver but not a clerk at the window, or a person who rings or bags your groceries. What makes some professions/professionals eligible to be tipped and the others not. I have not got a straight answer from any one on this. May be there is none. One reason I have heard often enough is that the people who are tipped are not well paid, so it is somehow imperative on the customers to tip them as if to take pity on them.
