Nothing feels quite so bittersweet as remembering what it felt like to read as a child, when you'd nestle in somewhere safe and let your imagination unfurl until you were sucked completely into a story in a way that doesn't really happen when you're an adult.
Many things conspire to rob you of this precious ability as you get older. It could be that you get trained to critique books even as your read them. It could be that you find it too hard to turn off at the end of a busy day at work. It could be that the grating snores of a partner you quietly resent keeps disrupting your concentration.
It could also be that the literature we read tends to take on a different quality, one less full of giants, chocolate factories and crafty foxes and more full of tortured protagonists, anti-heroes and - this year at least - sadomasochism.
Many adults - and I always scoff at them, such is my literary snobbery - get around this by reading nonsense like Harry Potter, rather than the literary classics befitting an intelligent person past the age of 16.
I scoff at them because I believe there are too many (far, far too many) great adult books to tackle during our sojourn on earth without feeding the brain literary baby food. But I guess a part of me is jealous of them, too.
That's why Roald Dahl - the great children's author of them all - is the first gift I buy a newborn in my family, and the first collection I reach for when it's my time to read them a bedtime story.
He understood, did Dahl, that children have just as much wickedness in them as they do innocence, that theirs is a world as full of secret, irrational cruelties as it is spontaneous hugs and kisses.
And so hateful witches turn children to mice, bitter old married couples play lethal tricks on each other and teachers lock children away in medieval torture tombs - the love in Dahl's peerless masterpieces of imagination and humour is always met in equal part by evil.
I devoured every Dahl multiple times over growing up, and so without so much as a glance back over those well-thumbed portals, allow me to present on Dahl Day my five favourite memories from the work of a writer who understood children better than any other - memories I will carry with me as an adult for the rest of my life, and dwell on from time to time to be reminded of what it felt like to read before I was well-read.
5) Mr. Hoppy's fantasy
In Esio Trot hapless, lonely Mr. Hoppy lies in bed and imagines being a braver, more romantic man - one who might win the love of his neighbour by beating up a gang of muggers as they attack her. As a teenager, and less frequently as an adult, I'd have similar fantasies. It's the noble side of male lust - the desire to be a somehow better person in order to win someone's heart. And like Mr. Hoppy, we have to eventually learn to make the best of who we are, rather than dream of what we're not.
4) The Twit's mistake
My all-time favourite Dahl line comes from The Twits, whose house doesn't have any windows in it to stop people walking past and looking inside. "It doesn't occur to them," the book reads "that windows were also for looking out of". For me, that is a perfect metaphor for the dangers of negative thinking, and a brilliant reminder that life is never as bad as it seems - it's all just a matter of perspective.
3) Mr. Fox's feast
One of the strangest powers literature can have is to feed you, when food or drink is evoked in such a powerful or vivid way it leaves the very taste in your mouth. Steinbeck's coffee... Hemingway's eggs... lots of great adult writers do it, but none come close to the moment when a ravenous Mr. Fox bursts through the wall of his adversary's chicken hut and begins his feast. My stomach is rumbling just thinking about it.
2) The BFG's farts
If any moment in Dahl's books illustrates how wonderful he was at getting into the minds of children, it is when Sophie from The BFG discovers that in the giant's world, the social etiquette about body wind is inversed. Burping is very, very rude whereas farting is no more unacceptable than a discreet belch. For little boys, this notion is as thrilling and wonderful as a river made of chocolate.
1) My Dad and Danny
Like most men, I've got many special childhood memories of my Father: driving through country lanes at 6am to set up his market stall, staying up extra late on the sofa to laugh at Only Fools And Horses... but few are as special as reading Danny The Champion Of The World together. Dahl's saddest, most poignant book - to boys and their fathers at least - captures perfectly the journey dads take from hero, to villain to friend, and it felt like a book written just for us. In my head, I suppose, it still is.
More Roald Dahl Day fun: