There are many indignities that come with age, like arthritis and hot flushes, but perhaps the most maddening of them all is the way one’s memory now plays tricks. Not small, harmless tricks, like forgetting where you put the car keys. No, I mean the kinds of lapses that begin with a burst of determination, a purposeful stride, and then utter blankness.

Last night, I sprang out of bed (or as much as someone arthritic can spring) and strode purposefully towards my dressing room. As I walked in, I turned back to look at my husband and admitted, rather sheepishly, that I had completely forgotten what I was looking for.

I thought that vaguely looking around might spur my memory. After all, a visual cue can sometimes unlock what the mind has selfishly hidden away. But there was not even a flicker of memory. Just clothes, all unhelpfully mute. So, I slumped back into bed sadly, in a state of unhappiness. Because surely whatever I was looking for must have been important, given the vigour with which I had launched myself out of bed.

My poor, long-suffering husband, accustomed to these lapses, tried to be helpful. “Eye mask? Hand cream? Your phone?” he suggested, forming a checklist of my usual nocturnal needs. None of these seemed quite right. Still, I retrieved all three before getting back into bed because I felt there must have been some important reason for getting up, and I was not prepared to return empty-handed. I felt a bit like I do when I get back from the shops with a bag full of unnecessary groceries but without the one thing I actually went for.

This feeling is utterly infuriating. That sense that something has slipped out of reach and is mocking me from the shadows of my own mind. I lay in bed knowing that I was missing something. My husband, wisely, said little more. Eventually, I stopped worrying and decided to channel my frustration into writing a blog post. At least then I could purpose the forgetfulness into something productive. Time passed, the minutes ticked by, and I eventually turned off the light, kissed my husband, and settled down for sleep. It was then, like the flicking on of a light switch, that I suddenly remembered.

I flew out of bed (well, rolled out, then hobbled, but with gusto) and strode again towards the dressing room, announcing loudly that I had remembered. My husband, who by now was half-asleep, murmured the obvious question: “What was it?”

“A shoe,” I responded with triumphant glee.

There was a pause. A rather loaded silence, I felt, from Hubby.

I picked up the shoe, feeling rather proud of my rediscovery, but then noticed it was somewhat dusty. Naturally, I announced that it needed a wash. So, I washed it, yes, that single shoe. At bedtime. With the seriousness of someone handling crown jewels. After putting it next to my dressing table to dry, and so that I would remember to take it to work the following morning, I returned to bed, satisfied.

But my husband remained completely mute. No raised eyebrows, no bewildered follow-up questions. He just turned over and went to sleep. He might have muttered mutter “jolly good” or something equally dismissive under his breath, but it could also have been a soft snore. And that’s when I realised how utterly crazy he thinks I am. Anyone who leaps from bed to retrieve and wash a single shoe surely deserves at least a raised eyebrow. But after all these years, the poor man has become immune to my eccentricities.

Now, for the record, there was a perfectly sensible reason for this midnight shoe. A colleague at school needed it for a lesson on stereotypes and how we make assumptions based on appearances. A single shoe, it turns out, can be an excellent prompt for discussion like who might it belong to and what type of person might purchase an Iron Fist stiletto sporting a set of teeth.

All very noble. All very educational. But at 11:30 p.m., the distinction between “noble” and “deranged” is slim. This was when I realised that my husband no longer believes that anything emanating from my mouth (or, quite frankly, my mind) is likely to make sense, so he doesn’t waste the energy interrogating it.

Perhaps our marriage has become gentle resignation to each other’s oddities. His silence was not lack of interest but a kind of mercy. Why demand rational explanations when none are forthcoming? As I finally drifted off to sleep, I reflected that this was a reminder that purpose and madness sometimes look remarkably similar. One person’s peculiar night-time errand is another’s dedication to her work.

The truth is, we all carry around our own single shoes. These are our strange priorities and little obsessions that make perfect sense to us and seem to be utterly bizarre to anyone else. The trick is not to worry too much about how absurd they appear. And at least I have one very clean shoe to show for it.