"Nobody reads a mystery to get to the middle.
They read it to get to the end.
If it's a letdown, they won't buy any more.
The first page sells the book.
The last page sells your next book."
(Mickey Spillane)
I think this holds true for all stories, for all books, not just mysteries. As a reader, I don't need the ending tied up with a sparkly pink bow. I like a good wrap-up, with maybe a few loose ends so I can imagine the story continuing to unfold beyond the pages. I'm good with a vague ending, one that's open to some interpretation. I don't care for cliffhangers, though. I don't want to feel manipulated into buying the next book in order to see how this one ends.
As readers, we put time and often money into a story or a book. We put our trust in the author, believing that he or she will deliver from start to finish.
As writers, we're responsible for safeguarding that trust. We must bring our readers out the other side happier, more entertained, more satisfied than when they started. We need to leave them better off for reading our work.
So, as readers, what's your favorite kind of ending? How do you feel about cliffhangers? As writers, how much time do you spend perfecting the ending versus the beginning? How do you leave your readers wanting, not needing, more?