“Writing is a delicious agony.”

Variant: the problems of the human heart in conflict with itself which alone can make good writing because only that is worth writing about, worth the agony and the sweat

Source: The People Look Like Flowers at Last

Source: Dragon's Teeth

"Horse Latitudes"

Source: Power and Innocence (1972), Ch. 11 : The Humanity of the Rebel
Context: Civilization begins with a rebellion. Prometheus, one of the Titans, steals fire from the gods on Mount Olympus and brings it as a gift to man, marking the birth of human culture. For this rebellion Zeus sentences him to be chained to Mount Caucasus where vultures consume his liver during the day and at night it grows back only to be again eaten away the next day. This is a tale of the agony of the creative individual, whose nightly rest only resuscitates him so that he can endure his agonies the next day.

Nobel Prize acceptance speech (1950)

Source: Secrets of the Dragon Sanctuary