Let me start off by saying that there wasn't any real parameters set in this debate; therefore, what kind of service, retail, food, or any other kind, that the customer would be dealt with was not specified. With that said, I will focus on the food service where "the customer is always right" is a kind of unspoken motto.
When ordering food and paying for it, it is only reasonable that the customer should get their way and if there are any problems with what they are inevitably paying for then that should be fixed to the customer's liking. If food services didn't take into account the customer's opinion then that service could do whatever they wanted, without any regards to the customer's wants, then they wouldn't have any business. Food services are there to provide food with the customer's opinions and wants in mind.