For the person who waits tables for a living, few things are more intense than the fear of being stiffed on the tip. Restaurant servers know what I'm talking about. When it is the end of the month and you have one more Saturday night shift left before rent is due, you are literally banking on your customers to keep a roof over your head. But for those who have never waited tables, you have to wonder -- are tips really that important? To find out, check out PayScale's recently released 2012-2013 Tipping Study.