The End. Really.

Of the many reasons for the significant presence of story in most cultures, there are two that tend to be set aside for later examination, where they become forgotten until, much like coins found in sofa cushions, they are encountered with some pleasure.

Story attracts us because of its tidal nature; it has a beginning and an ending. So many things in life seem to have no fixed starting point, nor do they work their way to some form of closure so much as they merely stop. If, perchance, they continue, they do so without our focus, with the result of our being surprised to notice them.

Memorable story tells itself through a combination of action and explanation. We're attracted to story by the promise of quest, which is action, and the explanation for the quest. 

Your own introduction to stories often began with a young person embarked on a journey "to seek his fortune,"or an equally young person recognizing some talent she must pursue.

Such stories also began with the equivalent filter of a storyteller, who declaimed, "Once upon a time--" or "In the city of X, there lived a man named Y, who--" Not surprisingly, you wanted out of such beginnings and into the action were to be taut with imagery and intrigue such as, "Stately plump Buck Mulligan came from the stairhead, bearing a bowl of lather on which a mirror and a razor lay crossed."

There was nothing unusual in you wishing for a story to begin somewhere, then have sufficient momentum to carry you along with it, out of your life events which, while not insignificant, were not yet of enough significance to satisfy you.

When a story ended, you were of minimal patience with "And they all lived happily ever after," which did not at all seem satisfactory. Even at that early stage, you were able to discern that happiness had a use-by date, more to the point, the tide had a habit of ebb and flow.

So what constitutes an ending?  Try this: Endings occur when the energy of an earlier mission or quest run our or are for the moment addressed.  Endings take place when nothing more from the present quest or mission are necessary.  Nothing.

Endings occur when the reader is left to sort the implications, then decide why this story feels over.