The work is an absolute necessity for me. I can't put it off, I don't care for anything but the work; that is to say, the pleasure in something else ceases at once and I become melancholy when I can't go on with my work. Then I feel like a weaver who sees that his threads are tangled, and the pattern he had on the loom is gone to hell, and all his thought and exertion is lost.

As quoted in Stranger on the Earth : A Psychological Biography of Vincent Van Gogh (1996) by Albert J. Lubin, p. 22