I can't find the quote on this, although I heard the sentiment attributed to Harlan Ellison.
I'm not sure how I feel about this idea. It's got two core assumptions: (1) that everyone can find something they'd want to do for 15 hours a day and (2) that it's possible to find someone to pay you for whatever (1) is. Just satisfying (1) is difficult: even on the weekends I sometimes find myself without anything I really want to do. Nevermind just one thing.
And yet there is a beautiful, appealling elegance to the idea. Recipe for happiness: find the thing you want to do, and do that. Why cast life as the quest to be happy with what you've do? Why not the quest to do what you'll be happy with?
Although "be happy with what you do" is an elegant answer, too. There are two business self-help books that my job has paid its employees to read in the time that I've been here: Who Moved the Cheese and Fish! I could summarize the former as "go find what makes you happy" and the latter as "be happy with what you have". Some people I know hate both books, which I understand, because both books are focused on playing by the rules of business and what some people really want to do are change the rules. But as general "rules to live by", it seems like one of them ought to be appropriate to any given situation. Either be happy with what you're doing or do something else. How hard is that?
Ah, so much easier to say than to do.
But back to my original quote: there's an implication in it that people can find one thing that they'll be happy doing forever. Oh, not necessarily, I suppose. A career can be a broad thing, spanning many different aspects. Even a job like "writer" or "artist" has wildly different parts to it: writers do outlines and research and revisions and summaries and query letters, as well as the actual "writing" part. Artists don't just paint: they have to get models and study anatomy and prep canvases and clean utensils and so forth. In theory, you could make a job out of doing just one part of those careers and have other people do the rest, although in practice that rarely happens. Likewise, in theory, you could make a career out of doing a bunch of unrelated tasks, all of which you enjoy.
But the implication remains: find that one thing you love enough to do exclusively, and you too can be happy.
I think I see that in the quote because some of my fondest memories are of obsessions. Times when I was absolutely obsessed with doing one thing, when I could do it for 15 hours a day and be happy, when I didn't want to do anything else. Like the fugue state I was in when finishing Silver Scales.
I don't know if it's common for my obsessions to bring me joy. There's an experiment I heard about with rats, where they put two groups in separate cages. One group got food pellets when they pushed a button, and the other got delicious treats for pushing the button. Once the rats had gotten used to this, the researchers deactivated buttons, so they didn't do anything anymore. The first group stopped pushing the button after a while, and looked for other ways to get food.
The second group kept pushing the button until they died of starvation.
Sometimes I feel like that second group, still pushing the button even though it's not working any more.
I've never been able to sustain that state of joyous-with-doing-one-thing for very long. Maybe a few months at the outside. After that, maybe I've finished the project, or gone on to a different one anyway, or keep working at it until it's done and/or makes me happy again (which sometimes does work: see Silver Scales.)
And I don't know which I should try to fix. Is the problem that I obsess, and the solution for me to stop doing it, to pace myself? Is the problem that I do try to pace myself, and I'd be happier giving my passions free rein? Is obsession part of who I am, and I need to find a way to make it work for me? Is there out there, somewhere, the one perfect thing that I can obsess over forever, and I need to keep looking for it?
I don't know. Pretty sure it's not that last one, though.