MYTH: “The customer is always right”.
TRUTH: The customer is not always right. They are (at times) wrong, wrong wrong!
TRUTH: The customer is ALWAYS the customer.
I keep this second truth in mind when I am negotiating, re-setting expectations, and resolving issues.
Treat your customers with respect, listen to them, and manage their expectations. They may not always be right, but they are always the customer!