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.
(..) lt's like a joke. lt's not a joke, it's an amusement park. lt's the best amusement park in the world. All you have to do is have fun. There's some pretty rough-looking customers here. How many of them are...? Guests like us? Who knows? That's the beauty of this place. lt doesn't matter. (..)1973 Westworld