Reminds me of a Jimmy Carr joke: "I was in a taxi when the driver said 'I love my job! I'm my own boss and nobody tells me what to do!'. I said 'Great. Now take a left here!' "
When doing something a customer asks for, you are doing something for someone's benefit (usually...).
When doing something the boss asks for, well, you may never know whether it makes any sense to anybody at all if the company sufficiently detaches employees from the results of their work. There are places where you just feel like you are wasting time for nothing.
Besides that, you can always (but not too often ;)) tell some particularly annoying customer to leave and pick up another one.
