"The whole difficulty lies in the question of if and how it is possible to say 'No' to this suffocating Superego imperative of enjoyment. Here we could recall the joke about John, who decides
to pay a visit to a psychiatrist because he wets his bed every night. He explains to the doctor that every night, a dwarf appears in his dream, saying to him: 'And now, dear John, we are going to pee.' And John duly pees in his bed. The psychiatrist advises him to respond to the dwarf's invitation with a determined 'NO!' John goes home, but returns the next day. 'I followed your advice,' he says to the doctor. 'When the dwarf appeared, and encouraged me to pee, I firmly said NO! But then the dwarf replied: Very well then, in that case, we are going to shit.'"

--Alenka Zupancic, from The Shortest Shadow: Nietzsche's Philosophy of the Two