If you're unhappy about your dining experience and you're considering not leaving a tip for the wait staff, don't be too hasty. Sometimes things that go wrong aren't their fault, and if the server has made any effort at all to help -- such as by bringing water, silverware, and such -- they deserve something at least.
When dining out in a foreign restaurant, be sure you understand the accepted etiquette for behavior, tipping, and treatment of the wait staff. Many guidebooks will help you out with tips, but it's better to have someone with you with a thorough understanding of the culture.