Tipping

From Jay Rayner in the Guardian

The naysayers argue that without tips we have no way of showing our approval or disapproval. Not true. We could show our disapproval exactly as we do now: by never visiting the restaurant again.
And how do you know who caused the problem? You've now created work for the manager. He has to now monitor his staff for performance with video recording and watching it and so forth to see who does an excellent job and who sneers at the customers. Unless you get a complaint (and you frequently don't with restaurants) you don't know which waiter caused the problem.
Tipping works because it does that job for you. A bad waiter doesn't get a tip. A good waiter does. Bad waiters quit and do another job.
A lot of jobs don't run on tips or commission and that's because they're more complicated than that. I've worked in places that tried to do bonuses for software bugs, and they ended up getting gamed - people would do the quickest, nastiest fixes just to tick off a bug.