While I agree for the most part with the previous answer, there is something to be said about stories that do not end in the way we expect. Stories that end in the way that the previous writer stated is only true of post-Christian western countries. If you look at Greek tragedies or literature from the East, endings are very different. Take, for example, Japanese horror movies. Does evil die in the end? No way! Often times there is no resolution. One is left feeling off balance. To make a long story short, stories that we tell are indicative of our worldviews, our hidden assumptions, the way we rationalize and think about the world. What if your worldview does not have resolutions or happy endings? What if your worldview is filled with injustice or random chance? The conclusion is simple: your stories will probably not have resolutions. So, to answer your questions, I would have to ask you a question. Whose stories?
A story is brought to its close by a resolution of the main conflict in the story. The resolution should convey a general insight or change that is made in relation to the main conflict. As in a typical plot diagram, the resolution is the final plot element of a story; it follows the exposition, inciting incident, rising action, climax, and falling action. While most readers prefer that a story end with a resolution that leaves them with a sense of satisfaction and that answers questions that might otherwise go unanswered, some writers choose to end their stories in ways that are unanticipated or somehow less than satisifying; the term for this is "anticlimactic."