The truly creative mind in any field is no more than this: a human creature born abnormally, inhumanly sensitive. To him, a touch is a blow, a sound is a noise, a misfortune is a tragedy, a joy is an ecstasy, a friend is a lover, a lover is a god, and failure is death. Add to this cruelly delicate organism the overpowering necessity to create, create, create — so that without the creating of music or poetry or books or buildings or something of meaning, his very breath is cut off from him. He must create, must pour out creation. By some strange, unknown, inward urgency he is not really alive unless he is creating.

As quoted in The 101 Habits of Highly Successful Screenwriters: Insiders Secrets from Hollywood's Top Writers (2001) by Karl Inglesias, p. 4. This has also appeared on the internet in several slightly paraphrased forms.