For the longest time I was told, "The customer is always right." Why? I think it was so we didn't lose clients, since customer loyalty matters or something...
But when I got into retail, I learned very quickly that a lot of customers are terribly wrong, and many of them might even lack a brain.
There is this amazing site called Not Always Right and it's a platform for people to share their stories of when others were so very wrong. Some stories make you mad, and some are so dumb that you can't help but laugh.