There were years when every story I wrote fizzled out, incomplete. Part of that was losing interest when I hit a technical problem I was incompetent at. But part of it was jumping on an idea that interested me and thinking that the interest meant that it was a story idea, and not a partial story idea. It would fizzle because it wasn't enough. So I started grabbing the little suckers by the throat and saying, "You're a story? So outline yourself for me. Prove that you're a story. Then I'll write you."
A stack of half-finished outlines is easier to handle than a stack of half-finished stories.
Though it can still be annoying. So you go back, use some tricks, take another shy at it -- and at least have the consolation of having spent less time than on a story.