How do you end a story?

How do you wrap things up? Does it have to be tidy and elegant, with no bits of extraneous sellotape and all the plot strands tied up neatly in a nice little bow? Or can we be a little messy, like life? Happy endings? Sad endings? Deliberately poignant endings? Or endings that are true to your characters? Shock-twist endings? Endings that allow for a sequel? Where do you want to leave your readers emotionally at the end of a book? Decisions. Decisions.