Sometimes I know exactly what they are in a story: an opening, say, where the heroine wins a magical helper, though she doesn't know it. Sometimes I even have stories where I know absolutely everything but one crucial part. Usually the exact solution to the problem. (Though the one that's plaguing me now: I know how she got the MacGuffin, I know what it does, I know she uses it once by accident, figures it out later, and uses it with forethought a third time, and what it does each time. But I don't know how to fit the parts together.)
The annoying thing is that the ideas will not die. Sometimes they might seem to, but they just go to sleep. If I even glance at the original inspiration, they hop back to life, yelping "Remember me?"
And do they have more of the story with them?
I think you can guess.