In 1965, Charlton Heston played Michelangelo in the Agony and the Ecstasy. The film dealt with the drama between Michelangelo and Pope Julius II. Basically, Pope Julius wanted Michelangelo to paint the ceiling of the Sistine Chapel. Michelangelo got annoyed by the Pope's constant nagging. The nagging was agonizing, yet the finished Sistine Chapel brought him immense joy.
As a painter, you will also experience an inequitable sense of glory when you finish a painting. It will be as if you've conquered an army, a math equation, or a mountain. Some people quit their day jobs to experience this glory. Steven Soderbergh, who directed Sex, Lies, and Videotape, Bubble, and Ocean’s Eleven, quit the film-making biz for the paintbrush lifestyle. If you decide to quit your day job like him, you will find that it takes some major dedication to not wind up under a bridge. Soderbergh should be okay for a while, though. He can make an Ocean's Thirteen if he needs to. In this case, putting it all on the line makes the improbable success and glory that much sweeter. It's like winning the lottery if buying a ticket in the first place was a huge sacrifice.