Update, listened to audiobook, 7/13/18: After listening to Gaiman read his own book, I still agree with everything I said when I read it back in 2013. The added fillip is to hear Gaiman doing the voices: of himself as a young boy, of Letty Hemstock, of Ursula Monkton, of old Mrs. Hemstock in particular! His voice is delightful, charming, inspirational and above all, plummy.
Gaiman can pull off an ending like very few can. Think about endings - books, movies, whatnot. If there's a particularly poor one - like the guy gets the girl even though he shouldn't, or there's a surprising explosion that kills off everyone you care about and ends the film abruptly, or the last painting in the series of eight doesn't fit the theme in any way - you leave thinking the entire thing you just read or watched or listened to stinks. It doesn't matter if the author of the work did something spectacular throughout - it's the ending that sticks with you.
In this case, Gaiman gives you something beautiful throughout - an achingly heartbreaking and simultaneously loving portrait of a childhood, which is mostly his childhood as I understand it. It has all the fantasy elements you know and love Gaiman for, so no, it isn't really how he grew up! But I believe, as will anyone who reads this, that this is how he lived his childhood in his mind. He has created some truly poignant moments for us that make us want to weep and gnash our teeth, and they are rooted in all our realities, which is why they resonate so well with us.
And that's what I realized over the course of this short volume. Gaiman's strength is in highlighting what matters - through the world he creates to layer on top of the real one - and those are faith, loyalty, sacrifice, affection, and yes, suffering as a means to better things. This is what his ending does. It's not so much a way to wrap up the story as it is to remind us that these are the things that are and should remain important to us.