Derive happiness in oneself from a good day’s work, from illuminating the fog that surrounds us.

The line frames happiness not as a passive mood or external reward but as something generated internally through purposeful effort. “A good day’s work” suggests disciplined practice—especially resonant for an artist like Matisse, for whom sustained labor in the studio was central. The second clause, “illuminating the fog that surrounds us,” widens the idea: work becomes a way of bringing clarity to confusion, whether personal, moral, or perceptual. Read this way, the quote links well-being to making—turning uncertainty into understanding—and implies that creative or conscientious labor can be both self-sustaining and socially meaningful by shedding light where there is obscurity.