Tipping is a lopsided reward for servers/bartenders
According to an Economic Policy Institute report, chefs make a median wage of $12.34 p/hour. This puts them under the poverty line. Granted, restaurant workers as a whole are only earning $10 p/hour, but someone working in the back of house has a static wage that doesn't change. A server or bartender's wage can improve dependent on how busy the restaurant/ bar is, and how well they perform their job.
And let's compare how long a server works compared to a chef -- "... the guys in the kitchen work 8-10 hours, and it's well known that at a busy restaurant, they make half the amount a server can make in a five-hour shift." Less pay, more hours. Even more disturbing is that it barely leaves them any time in the day to play Madden '15.