Remember, the 'customer' is always right. [=never argue with a customer]
He is one tough/tricky 'customer'. [=he is a tough/tricky person]
The company has good/poor 'customer' service.
(..) StanIey Ipkiss? Hi! I'm Peggy Brandt from the Tribune. I canceIed my subscription because they kept steaIing-- No, actuaIIy, I want to ask you a few questions. ReaIIy? About what? RipIey Auto Finishing. You're a customer, aren't you? Me? I don't even have a car. You know, 'cause they poIIute. (..)1994 The Mask