I generally always tip unless service sucks, but only because I know waitstaff are paid crap and usually working DM's are not paid at all. What I wonder is, how and why is that? How is it that over time restaurants have been able to condition customers to pay the bulk of their waitstaff's salaries AND get the IRS to basically sponsor it? How and why is it acceptable in the SCUBA industry for a dive charter to not pay a DM one stinking penny for working, but yet expect the customers to all chip in for the DM's income? If you don't want to pay him, why the heck should I? It is the dumbest thing ever and I don't understand why it is that way. When you take your car to the repair shop, you get a bill for the total amount due from the shop. You don't pay the shop the amount they charge you and then tip the actual mechanic who did the repair. The mechanic is paid for his job from the shop and the shop includes their cost for that mechanic in what they charge you. It's the same way with nearly every business except restaurants, bars, and SCUBA charters. It blows my mind. News flash to bars, restaurants, and dive charters. PAY YOUR EMPLOYEES FOR WORKING!!!! DON'T EXPECT CUSTOMERS TO PAY YOU FOR SERVICE AND THEN ALSO PAY THE PEOPLE WHO PROVIDED THE SERVICE. I'm guessing there will be a bunch of replies about how expensive dive charters, eating out, bars, etc... would be if the businesses had to pay their employees and I honestly think that philosophy is a big pile of crap. These industries only do it because they historically have gotten away with it.