Looking to fail? Make sure everyone in IT tells everyone outside of IT, "You're my customer. My job is to exceed your expectations" (or, worse, "make you happy").

Employees outside of IT are not IT's customers. They're IT's colleagues, with whom IT collaborates as equals if anything good is going to happen for the company as a whole.

Legitimizing the idea of internal customers puts IT in a subservient position, where everyone in IT has to make their colleagues happy, whether or not doing so makes sense for the business, let alone whether it encourages the company's actual customers to buy more products and services.