Customers are allowed to be friends too

The man who secures a contract from a customer and turns it in and ends at that point, is generally a very poor salesman. The man who obtains a contract, makes sure that it is properly recorded, keeps in touch with it through its various steps, until its completion, and then visits the customer afterwards to see that he is well satisfied, is the man who is co-operating in all the details. This has the further advantage that it generally makes a friend of the customer and thus adds to the value of the salesman to the company. — W. C. L. Elgin