Balzac

Mental work, labor in the higher regions of the mind, is one of the most strenuous kinds of human effort. The quality that above all deserves the greatest glory in art is courage; courage of a kind of which common minds have no conception. ... To plan, dream, and imagine fine works is a pleasant occupation, to be sure. It is like smoking magic cigars, like leading the life of a courtesan who pleases only herself. The work is then envisaged in all the grace of infancy, in the wild delight of its conception, in fragrant flowerlike beauty, with the ripe juices of the fruit savored in anticipation. Such are the pleasures of invention in the imagination. The man who can explain his design in words passes for an extraordinary man. All artists and writers posses this faculty. But to produce, to bring to birth, to bring up the infant work with labor, to put it to bed full-fed with milk, to take it up again every morning with inexhaustible maternal love, to lick it clean, to dress it a hundred times in lovely garments that it tears up again and again; never to be discouraged by the convulsions of this mad life, and to make of it a living masterpiece that speaks to all eyes in sculpture, or to all minds in literature, to all memories in painting, to all hearts in music -- that is the task of execution.

Balzac, Cousin Bette