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.
(..) to be a monster called "No-Face." And he says that you let him into the bathhouse. I did let him in. - Are you serious? - Yeah. I thought he was a customer. What? He's a monster. He's already swallowed three people. Found it! Here it is, Sen. - Hey, we're busy, boiler man. (..)2001 Spirited Away
(..) - No buts or I'll turn you into coal. - You hear me? - Ahh! It's here. Hands down. You'll insult our guest. Look, a valued customer. Welcome to our baths. Ahh! Eww! Ohh! Oh, it's money. Sen, take the nice customer's money. (..)2001 Spirited Away