For the last few days I was mostly bed-bound, plagued by some inexplicable deep exhaustion and an everywhere-achiness I can’t seem to label. It’s allergy season here in the Willamette Valley, and for a while I thought that maybe I’d been stricken by a very bad bout of hay fever. But did hay fever really strike a person this way, with all this sweaty achiness? Maybe it was just a cold, but why would a cold fell me so thoroughly and non-negotiably. All the tasks I attempted to do from bed—reading, answering e-mail, even sleeping—I had to abandon. I’m sorry, I kept saying to my husband. I don’t know what’s wrong with me.

Meanwhile, my unoccupied, meaning-seeking human mind was off and running, spinning out possible explanations for my sudden incapacitation—an autoimmune disease? some kind of cancer?—and scenarios about what would happen next. By far the worst thing I imagined was that I’d arrived at some permanent state from which I would never emerge—I was sentenced to live out the rest of my life in a chronic state of bodily distress.

But, for all the multiplicity of things I imagined, my active brain was singularly focused on bleak outcomes; I could not conjure a scenario of getting better.

Today, I am better, and I could not be more grateful. And I have been left thinking about the nature of imagination, the way it so often dives to worst-case scenarios. I am sure this tendency has to do with the exigencies of human survival. We have to imagine the worst in order to protect ourselves. If we can imagine a bad outcome fully, we might be able to prevent it—or at least plan for it.

What of the imagination when it comes to story-telling? Imagine more deeply! I say to my writing students again and again. Almost any writing problem can be solved by sinking more deeply into the imagined situation. We go to stories to learn about “people with problems” as the writer Ken Haruf says. Happy people, Tolstoy reminds us, are not so interesting to read (or write) about. So usually, as a writer, one’s charge is to imagine the worst. In a writing situation that isn’t always easy. My students have a tendency to be too kind to their characters. Don’t make it easy on them! I implore. Tighten the screws! And the good ones, those who have the fearlessness and storytelling chops, begin to relish the challenge. Take that! And that! And that! Once you get going it’s gratifying to imagine deeply and direly.

But for my own life I’d rather keep my dire, downward, worst-case-scenario-spiraling imagination in check. I’d rather believe, however wrong I am, that the future will be rosy—full of bright prospects and fine health. So now I am singularly focused on imagining a life in which I’ll never be sick again.