Am a few beers into the night, so I thought I'd throw my two cents into this thread.
Bukowski appeals to me for the simple aspect that I like my art full of pain. Bukowski's work is, first and foremost to me, primarily about the pain of life. The drinking, the women, the wandering are all symptoms of his pain. His art is his release. My vicarious release.
Pain breaks down the spirit. Everyone succumbs. The pain will wear everyone down. Cause the spirit to wane.
This is when the art appears. It forms, or perhaps takes form, at the point at which the pain starts to overcome. When the spirit wanes. Art is the release of the pain. Spirit is the impediment of art. As long as one is capable of sustaining the spirit, no release is necessary, no (true) art is formed.
But again, I think of pain and art almost synonymously. Perhaps antonymously (is that a word?). Okay, maybe just in subtle opposition.
More likely, as mjp and others indicate, it means very little and he is laughing his ass off at us while drinking a warm beer in Hell...