“I am smiling,” I said.“No,” she said, with a slight edge that I recognized immediately — the edge of someone who is trying to be patient with a difficult subject — “I mean, actually smile.”

The problem, which I have never been able to solve, is that my smile — the genuine, spontaneous, I-mean-it smile — is a lips-together situation. Something about the size relationship between my teeth and my lips (and possibly my cheeks) produces, when I attempt a full, toothy grin, not warmth and good cheer, but an image closer to a demonic figure from a medieval painting. The kind where the demon is about to do something to a sinner that involves fire and possibly biting.

I know this because I spent a certain number of hours when I was younger trying to smile in front of a mirror. I had noticed that some people have these wide, open, luminous smiles — lips naturally pulled back, teeth exposed. They have the sort of smile that makes you feel, when it’s directed at you, that you are the most important and delightful person in the room. I wanted that smile. I tried to produce that smile. What I produced instead suggested Jack Nicholson in The Shining (1980).

So I stopped trying. “I’m just not a smiler,” I said to myself, and since that day, I keep my lips together and hope for the best.