I'm inspired by Sarah's post about beginnings. I always think beginnings are the funnest part to write, because every possibility lies before you, and any direction is possible.
Endings, on the other hand . . .
Thriller writers say the story stops the moment the tension is released. Action, explosion, kidnap victim recovered, and boom--the story's done.
Mysteries aren't a whole lot different, I don't think. I always love Agatha Christie's ending: "You know what we need, dear? A nice cup of tea." The books don't meander on, exploring where we're all going to go now that the excitement is over.
For my own taste, I like a little coda at the end of a book. I like to know what might happen next. I want a clue as to how the characters will go on, now that the crisis is past. Will they stay together? Bid each other a teary farewell? Start a new life in a new place? There will be new complications and challenges in characters' lives, and I love to have a hint of that. I like to think, when I put down a book, that the characters in it go on living even though I can't read about them anymore.
And if I care that they go on living, then the writer has done her job.