There are a great many things to dislike about modern parenting trends – take your pick from helicopter to snowplow to Fafo – but the least appealing, perhaps, is the temptation present in all of them to treat raising a child like an extended school project.

The latest addition is something called 18 summers, in which clingy parents count down the school holidays they have left with their children before they leave home, pre-grieving the end as they go. There is no quicker way to ruin something than by filtering it through an internet trend, but this one is particularly insidious: an invitation to inject weird notes of anxiety into what might otherwise be an unstudied thing.

Let’s put to one side for a moment the fact that, in these economic times, kids don’t stop going on holiday with their parents until they’re roughly 35. The idea behind the “viral concept” of 18 summers – tagline “you only get 18 summers with your kid” – is to remind us that life is short and we should cherish each moment, a banality that, if it is ever true, is particularly untrue during the summer holidays, which are very, very long indeed. I would rather sign up to a movement called 18 minutes, in which we recognise the time-warping effect of the slow-crawl towards September, or even 18 seconds, in which we study the fascinating variables in time perception as it relates to unstructured periods with children, which might also be marketed as 18 millennia.

Eighteen summers on the other hand is designed, like most social media trends, to make us feel as if we’re misusing our time by showing us how other, better motivated people are using theirs. This is achieved via a set of social media posts carrying the 18 summers hashtag and which, no matter where in the world the images are generated, looks like a set of adverts for Center Parcs Longleat.

There has always been something creepy about the formalisation of quotidian parts of life, and I would put the phrase “making memories” into that category. It’s the animating ethos behind 18 summers, which comes with a retail shelf full of diaries, binders and other products to ensure we document every precious moment with our children – without enjoying any of them. I’m currently in New York, ground zero of acute parenting trends, where “experiencing joy” may be tackled with the same, furrow-browed intensity as “learning Mandarin” and where parents can become so feverishly intent on “making memories” for their children that they badger them into a state of complete mania. (In this world, going for a bike ride becomes so fraught with meaning it becomes Going For A Bike Ride and you’d better hope it hits that platonic ideal).

The bigger drag behind this concept is the need to turn every last human impulse into an item on a to-do list. Do you enjoy summer while also finding it enraging and boring? Well, try holding it up against an idealised version that relies for its power on a sense of loss, fear and competition with others. The word “magical” hangs heavily over this scene, too, and, who among us needs reminding that anyone who uses the word magical more than once or twice a year is a joyless weirdo. Other phrases encountered when you browse the endless Instagram reels around 18 summers: “ultimate family formula” (sounds fun!), “three steps to deepen your relationship with your child”, and “holding sand”, which refers to how fast the time goes (although in the case of this particular scene, not fast enough).

All of this is, of course, just another form of parental overreach, a way of normalising and celebrating controlling personalities. The flipside to 18 summers is the romanticisation of our own childhoods, in which, to listen to us go on, we spent six weeks out on bikes like the kids in ET rather than, say, inside watching telly. Still, no one interfered with us much. I took my kids to a climbing wall this week – making memories! – and it was like a comedy sketch, watching parents stand at the foot of the wall directing their perfectly able kids to the top. (“Honey, put your left foot on that one diagonally – no, not that one, the one next to it; up and to the right, yep, yep. YES! Good job! You’re so good at this!” As one dad standing next to me muttered bleakly, “back-seat climbing”).

I love the summers. Even when things get frazzled towards the end, I love the sense of having nothing to do, which makes a walk to the shops with my kids something to draw out for as long as we can, rather than race through to get to the next thing. The whole point of summer is that you’re not held to account, or a schedule, or in this case, a hashtag. For a short time, we can inhabit that state hovering right on the edge of boredom that – if we don’t ruin things by overthinking – seems to go on for ever.

• Emma Brockes is a Guardian columnist