The customer is always right

In the american and british service/retail sector employess are often taught this motto. However this often leads to comprimise with unreasonable customers taking advantage of good nature.

In contrast in France, the customer is viewed with mild contempt and annoyance (I'm sure you've heard about french waiters). This often whips customers into shape and make them more considerate and polite.

Which circumstance do you prefer and why?

Clearly human nature sucks and both options involve one side hurting the other for no good reason so my choice would depend on if I was the waiter or customer.