My husband for many years worked as a waiter in expensive restaurants. I can tell you that he made way less than minimum wage as his salary. He could make good money on his tips but worked very hard for it. I believe that a good waiter or waitress deserves a good tip if they work hard for it. I refuse to pay more than required for lousy work. Generally speaking we over tip because we understand the work that goes into a meal. I also feel that if you can afford to go on a cruise then you should have no problem paying for something that was earned. If the service is that horrible, report them early on in your trip and hopefully it will be taken care of.