Bad stories end quicker, and good stories get right to the point.
A short story can be as short as a paragraph or as long as 50 pages, so you have tons of freedom with which to work. So you've written a story and your mom says that it's super. You'd rather break into the pages of The New Yorker and get offered a cushy teaching job at a liberal arts school in Maine. Slow down, bucko. So don't send us hate mail.