I don't think I've ever shown anybody this, but I have an ongoing list of about 4 years cataloging all of my "movie ideas." It's a long list and most things never move off of there because of the symptom that gave this post its title. Some ideas aren't a story. They're just a hint of one.
Sometimes, they're just the title. Here's an example from a few years ago, and this is all I have written down for it.
Clearly it'd be a movie about a heist at a comic convention, but that's all I've ever done with it. (And I swear, if you steal my title and make a million dollars off that movie, I'll, well, probably go see it because it just sounds awesome.)
I have tons of these types of ideas. And these are the kinds of things that people walk up to writers and suggest. "How about a movie where ..." and the basic premise is laid out.
But that's the easy part, having an idea.
It's making that idea into something worthwhile that's the trick.
The reason I'm saying all of this is because right now, all I have are the hints. I have pages full of the hints.
And even if we're not talking about writing, I have a life full of the hints.
I'm ready for them to be a story.