It happens every time I write a short -- I get started, write what feels like a little over half the story, and then I get stuck. I don't know where it wants to end, or how much longer it wants to me, or I know where I want it to go but not how to get it there. So I flail, and I revise, and I abandon the story for a week or more, and then I come back and flail at it some more. Half my WIPs are still IP because I have no idea how to end them.
Blah. And feh.