Nurses commonly bid for shifts. Undesirable shifts pay far more than desirable ones. Christmas morning will pay far more than an ordinary Thursday afternoon. I

Nurses commonly bid for shifts. Undesirable shifts pay far more than desirable ones. Christmas morning will pay far more than an ordinary Thursday afternoon. I guess that isn't exactly flat wages, but it isn't tips either. I think it beats both. So at the restaurant, early evening on Valentine's Day would pay a lot more than the late afternoon on an uninteresting day.