One of the biggest factors affecting customer satisfaction in the service industry is the consistency of the service. In the service industry, the service is working when it is going unnoticed. We provide basic services and people expect them to be done the same way, on the same schedule, every time. People only really pay attention when there is a mistake.
Take a dry cleaners for instance. A guy brings his shirts in every week and he wants to know that he will be able to pick them up at the same time he always has and that they will be uniformly pressed and starched. He pays you and goes home and doesn't think about his dry cleaning.
But if one day there is a shirt that was not pressed or was ripped, the whole routine gets interrupted and the guy starts to look for a new dry cleaner. You have to be consistent to keep the customer.