When "May I help you?" sounds more like "You don't belong here."
When "What is the problem?" implies that the customer is the problem.
When "It's against our policy" could have been uttered by a robot.
When a fifth hearing of the recorded line "Your call means a lot to us" sparks the thought: "Then why won't you take it?"
When "That's not my job!" really means "I'm not going to help you."