Like Chuck Close (“Inspiration is for amateurs — the rest of us just show up and get to work.”), Isabel Allende (“Show up, show up, show up, and after a while the muse shows up, too.”), E. B. White (“A writer who waits for ideal conditions under which to work will die without putting a word on paper.”), and Tchaikovsky (“A self-respecting artist must not fold his hands on the pretext that he is not in the mood.”), Watterson speaks to the importance of work ethic and grit — but, like Freud, he places playfulness at the epicenter of creativity: It’s surprising how hard we’ll work when the work is done just for ourselves. And with all due respect to John Stuart Mill, maybe utilitarianism is overrated. If I’ve learned one thing from being a cartoonist, it’s how important playing is to creativity and happiness. My job is essentially to come up with 365 ideas a year. If you ever want to find out just how uninteresting you really are, get a job where the quality and frequency of ...