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.
(..) Four new tires! I can't-a believe it! Four new tires! Grazie, Mr. Lightning. Grazie! - Would you look at that! - Our first customer in years! I am filled with tears of ecstasy, for this is the most glorious day of my life! All right, Luigi, give me the best set of blackwalls you've got. (..)2006 Cars