If you make an appointment and just don't show up, you're either very forgetful or inconsiderate. Your time is no more important than the person(s) providing you service.
This is just a bit of a rant due to a client not showing up. I go turn on the heat, get the towel warmer going, set up the massage table, and basically set everything up nice? No call/no show. My time is worth nothing to this inconsiderate individual.