The big things that make people happy are, in me, mostly qualified.

Yes, of course I am happy when the children slip their little hands in mine and whisper Important Things on the way to school, but it is acutely tempered by how fast they are growing up, and how the day will come – soon – when they won’t tell me anything at all. Instead of making a huge fuss about a frog in the road, they will simply grunt, just as the five-year-old, after a lifetime of wearing nothing but polyester Buzz Lightyear, Spider-Man, Iron Man and Rocket Raccoon costumes in strict rotation, recently stickily imparted that she was going to dress “nomly” from now on.

And I love being a writer – I truly do, I know I am incredibly lucky – but of course a) what’s in my head is always a lot better than whatever remnants of it I manage to capture on paper, b) the next book is always vastly superior to the one I’m currently writing, and c) writing is as precarious a job as any other, and could all end at any point.

And of course there is no true joy in the Nelson Muntz pleasures – ooh, doesn’t the school bully look rough on Facebook! Ooh, that talented actress whom I unaccountably dislike is getting divorced! – because they are unwholesome, and do us no good.

So I absolutely believe in always being alert to the smaller, unconditional joys. A new Viz in the shops. A new pen – I firmly believe that out there somewhere is the platonic form of a sketching pen, and that one day I will find it. Red lipstick. Any new episode of Doctor Who, any old episode of Friends, or that very specific episode of The West Wing where Josh goes to see his trauma therapist.

Pink in the sky. Looking at a picture of Snoopy dancing, or indeed dancing myself (although the children will soon learn to shout, “Oh GOD Mum stop dancing it’s SOO embarrassing”, so that’s a double-edged pleasure too). Singing in a choir might be the kind of thing they tell you to do in middle-class magazine problem pages, but boy does it make you euphoric. That precise moment when the lights go down in a cinema or theatre, and you feel the expectant hush. The state of having done exercise that day (the doing of it is rubbish, obviously). Getting so deeply engrossed in a book that you can’t remember where you are and the bathwater goes cold. A song that exactly suits your mood popping up on the radio. Sharing stupid jokes and wine with chums, or with the world on Twitter, a pleasure my husband finds as foreign as I do the evident enjoyment he takes in cycling 140km up a freezing mountain at any given opportunity.

A stiff gin and tonic on a Friday night. Friends, of course – the older the better. Eight hours’ sleep. Going to the airport, whether heading out or picking up – both are full of pleasurable anticipation. It is the little parcels of cheer, after all, that keep us from worrying too much about life’s big stuff.

But then, sometimes at night, I grasp it. When all is safely gathered in, homework done, work completed, everything cleared away, tears wiped, news and jokes shared, and the house goes to sleep (early – another small thing that makes me happy), and it is just us, in that deep heart of marriage – two people, holding hands in the dark – in that instant before I fall asleep I do think, perhaps life could just be this, and I wouldn’t need to feel the cold winds of old age and illness and worry and problems and the usual wheel of life. Perhaps we will always be this way.

And for that very tiny second, in that infinitesimal, hovering element of time before I dive into Tardis dreams, I am completely happy, and it feels a lot like grace.

Jenny Colgan’s books Summer at Little Beach Street Bakery and Polly and the Puffin (the children’s version) are both out‎ on 26 February