"Customers are always right". The infamous phrase a buyer would always abuse to assert their imaginary "rights". Surely for those who have been on the working field for some time would able to relate it to their nightmare experience so quick, they can list down a couple of scenarios before you can finish saying that stupid phrase.
Take my case. I have been working in the services field for some time; it is my job to solve our clients' problems. A mundane Tuesday will just be mundane without this strange caller needed answers...