There is a moment that arrives every spring here in the Adirondacks, usually sometime in April, usually without warning, when something shifts. The air changes. The light feels different on your face. You step outside and realize, with a small jolt of disorientation, that you feel alive again.

And then, almost immediately, comes the confusion.

You look back at the past several months and wonder: who was that? Who was the person who moved through the days in slow motion, who gained a few pounds, who responded to perfectly ordinary situations with a kind of gray, low-grade grumpiness?…