Endings are tough to write, though. Real tough. Even mega-bestselling authors frequently end with turkeys but hopefully the ride there was enough fun to overlook them. (They never are, not really, but I'll be kind. I didn't even name names today! I must be mellowing...)
A reason occurred to me why this might be so, in genre fiction especially. In a crime novel, almost all of the time the good guy triumphs over the bad; the criminal goes to jail, gets the chair, or has his brains splattered over a nearby wall. Sure there are the minority cases where the bad guy gets away to fight in a later book in the series, and on really rare occasions actually blow away the hero. None of this is a surprise.
That good must (kind of) triumph over evil in crime fiction is as constraining as it is expected. How on earth does a writer do it and bring something (hopefully) fresh to the table? Is it even possible?
To me, a good book has its own style, its own voice. The ending may not have to be unique, but it has to be consistent with the style/voice that got me there. And it can't be something out of the blue. It may be inevitable from a convention standpoint, but it needs to make logical sense and hopefully, have aspects that are unpredictable yet copacetic with all that had come before. The actual ending "event" may not be a shock, but you should be surprised at something to do with how you got there.
Nothing's more disappointing than reading an exciting, edge of your seat potboiler and having it end with a sudden and single shot from the hero's gun when that surprise element is lacking. In a hugely popular book and as depicted in a hugely popular movie, the hero is floundering in a dark basement, the serial killer trapped and lurking nearby. A noise, a shot: the killer's dead. We're deprived even of a skillful shot, a quick draw, or a bait/trap scenario. We don't even get a ricochet. We get the next thing to pure dumb luck.
Does it tarnish the enjoyment I got from the book leading up to that point? You bet. Will most people even remember how it ended? Probably not. That's probably too bad.
I think I fall in the "if the author doesn't know how the book will end, how can the reader?" camp, as opposed to the "know the ending first" kind of writer. On the other hand, if I were freed from the traps of my own earlier chapters, I could maybe come up with something unique and then write towards it. But then I'm constraining all of the writing that comes before the end...
I think the only real answer is to write well, don't compromise or settle, and above all make the ending consistent with everything that brings the reader there. Dance with what brung ya. But that goes with so many things, and like most of them, is easier said then done.
(Clearly I'll forget how I closed this entry momentarily.)