There are some days when being a teacher is the best job in the world. Days when working with young people is fresh and rewarding and amazing. When you know that you are doing a worthwhile and important job.

Today is not one of those days.

I’ve been a teacher now for three years and it’s not like it used to be, back at the beginning. Back then I worried about whether I could define irony under pressure or spell propaganda (possibly); whether I could remember which one was George and which was Lennie, and which one was the Duke of Clarence and if Juliet was a Capulet or a Montague. And, even more terrifyingly, whether I could persuade the children to stay in the room, in their seats, and maybe even write something down occasionally.

When you start teaching, well when I started teaching, that’s the stuff I worried about. You watch other teachers in wide-eyed wonder as they seem to make the children shut up and listen. It all looks like witchcraft.

I’m not saying all that’s in the bag but that’s not the fact that I can’t spell onomatopoeia that wakes me up at 5am, and then keeps me awake, one eye on the winking green numbers of the alarm clock until it’s time to get up. It’s not even the exam results or the Ofsted shenanigans. Although I can’t say all that stuff doesn’t give me the heebeegeebees. Really not.

What keeps my eyes pinned open, my mind galloping, even when my body is dog-tired – it’s the children.

Of course it’s the children.

I’ve blogged before about how many people are wide eyed about how BRAVE I am to teach REAL LIVE SCARY CHILDREN. Like I’m some sort of distinctly unglamorous lion tamer. But it’s really not like that. What I face every day are not rooms full of wild animals but just, you know, people. Sometimes scared, occasionally hilarious, frequently grumpy, always vulnerable.

And after a few years you get to know these children and you start to care about them, not as a crowd but as individuals, as people with sometimes extremely crappy lives.

And sometimes you can help. You can give a listening ear, you can hand out biscuits and a little bit of advice here and there. You can recommend books and occasionally you can even get them to pass a few crucial exams, if you’re willing to sweat actual blood and give up all your personal life. And most teachers are prepared to do that, and more.

But mostly, the help you can give is – at best – pretty marginal. You get to know the children, and then you have to stand by while life buffets them about and knocks them sideways. You have to stand on the sidelines watching, helpless and mute, while they make the mistakes they are destined to make, biting your nails and wishing you could look away. You have to watch as they kick out at the world and then wince as – in the words of the song – the world kicks back, a lot flipping harder.

As a secondary teacher, by the time you meet your charges, it’s all pretty much a done deal as far as their future is concerned. Genetics and family and culture have all combined to lay down the tracks that these young people are trundling along on. You can oil the tracks, you can speed up progress, but if a crash or a derailment is coming, you’re powerless to stop it, more or less.

In the last few weeks I have witnessed a few pretty spectacular crashes. Most of them were absolutely and completely predictable, but predictable doesn’t mean preventable. I’ve been buying a lot of man size tissues, and baking a lot of cakes, and then lying awake fretting and worrying and hoping that things will soon get better for them, for all of them. But knowing that – probably, for many of them – it won’t.

What I have learned, more than anything else, from three years of teaching is that age is a very very ambiguous concept. Getting older doesn’t mean becoming more mature. Many many adults of my acquaintance are, to all intents and purposes, just children with more expensive clothes and hobbies. Many adults haven’t developed emotional maturity and they are still every bit as frightened and anxious and flawed as they were as children. On the other hand, some of the children I teach are emotionally mature, self-aware and a great deal more grown up than many adults. And often delightfully lacking in the kind of bitterness that can so often set in as life takes its wearing toll on us all.

What really separates out the teenagers from the grown ups is not maturity or emotional control or even some sort of perspective on the world. What we have acquired, what sets us apart from the teenagers is this, and only this: experience. Knowing that everything passes, sooner or later. That pain and pleasure may seem overwhelming and devastating but they both fade, if you hang on in there for long enough.

One day, your broken heart will be all healed and perky again, just in time to get it broken all over again, but this time in a fresh and different way.

And one day the worries that woke me up at 5am about that child, and his pain and the horror of his life – they’ll have faded away. To be replaced, no doubt, with a fresh and different set of worries about another child altogether.

So, this is what we should be passing on to the next generation: hang on in there, because this too will pass.

We’re all the same, and, young and old, we’re all in this together.