Our first full day after we made it back to London was also my birthday—my fiftieth, in fact. The younger was therefore feeling especially magnanimous, and agreed to accompany me to the Kenwood Ladies’ Pond, though she demurred at venturing into the water herself.

“I’ll just put my feet in,” she declared, to which I responded, “I don’t think you can! It’s in or out!”

I hadn’t been to the pond for a few years, and always find it slightly forbidding. The woman at the little ticket office at the entrance had a quizzical look on her face and I sensed we would have to prove ourselves in some way somehow to be permitted to enter, perhaps answering a riddle or performing some kind of feat.

“Hello, I would like to swim please!” I said.

She nodded.

“And she, I gesture to the younger, “doesn’t want to swim … can she just sit and watch?”

“Well, not when it’s crowded,” the woman said.

There was a pause as I considered whether this was a yes or a no.

It was about 9:30 on a grey weekday morning. I couldn’t really see into the pond and its environs past the ticket office, but it didn’t seem especially busy.

The woman sighed and reluctantly added, “I mean, at the moment, it’s fine.”

I now sighed with relief but the woman was not finished with us.

She narrowed her eyes and scrutinized the younger.

“Are you sure you don’t want to go in?”

The younger didn’t reply and I hastily jumped in.

“I tried to persuade her but she said she was sure she didn’t want to—and she didn’t bring her suit,” I added.

Throughout this exchange the woman was only making eye contact with the younger.

“Luckily for you,” she confided, in the quietly victorious tone in which one might say, “checkmate,” “we have loads of extra swimming costumes.”

I was still looking at the woman and not at the younger but I could imagine the latter’s expression, which was confirmed by the woman, who now howled with laughter and threw her head back.

“Oh my God, she just gave me That. Look,” she said to me, between guffaws.

I knew instantly what look she meant.

She continued, “That, ‘Mum. NO.’ look—my sixteen-year-old has perfected it.”

By now she had her phone out and was scrolling through pictures.

She showed us.

“See that’s me and my Mum, and we’re laughing and look at her!” she screeched.

She pointed to the third figure in the picture and then looked at me, shaking her head.

“She’s just looking off to the side!” she exclaimed, still incredulous.

I obliged her by looking but I really didn’t need to because I’d seen this picture a thousand times before, many of them on my own iPhone screen in the previous week: the happy family snap punctured by a teen’s withering kill-me-now side-eye, a move they seem reflexively to perfect in the preteen years, and which I find admirable and irritating in equal parts: admirable for its dogged refusal to perform bonhomie on cue, to render oneself Instagrammable. Irritating for how mercilessly it exposes my own readiness to perform and demand the facial expressions the algorithms associate with domestic felicity.

As reflexive as the younger’s side-eye was my own rote participation in the ticket-office woman’s good-natured complaining about her daughter.

Tipping my head at the younger, I confided, “Well she’s only 13 and she’s clearly already got it down! She’s precocious!”

I didn’t need to look in the younger’s direction to know that she had shriveled and expired from mortification during this exchange.

Even as the words tumbled out of my mouth I knew I would pay for this and, indeed, as we walked away the younger stared stonily ahead, muttering unspeakable things under her breath and shaking her head.