Waiter Gods are the all knowing, unseen entities who control the ebb and flow of the great tip continuum. They are mysterious and unknowable ,but their wrath can be swift, cruel, and could possibly prevent you from makeing rent this month. As their name implies their dominian of power is over Waiters, but also has been know to effect assistant managers and unscrupulous bus boys.
If one whos income is dependant upon tips is themself a bad tipper then the Waiter Gods insure that mere spare change shall be returned to them with increaseing frequency. If the blasphemer does not repent he can expect to get screwed out of nights and weekends too. The Hindu religion refers to this as Karma, but this is naive and underscores the true power of the Waiter Gods.

When you eat dirt for the first time and leave your family to build a shack in the woods