It's often said that a writer who sits around waiting for inspiration to alight on her shoulder like a luna moth will not end up writing very much. I know the point is to encourage us to seize raw material and shape it no matter how lumpy and imperfect it seems at first, to urge us not to be too precious about our writing. There's definitely something in that.
And yet, there are ideas that jump into the brain, seize it, shake it. There are stories that cannot be turned away anymore than they can be forced. There is such a thing as inspiration.
Perhaps it's just a case of keeping lines in the water until that fish bites. The magic idea that seems to come from nowhere has actually fed on months of patient work. It stays because at the moment it wings in, there is a writer waiting there to meet it. Maybe the aroma of good honest sweat is what draws the fairy godmother in.
When it happens, it can't always be explained, but it's one of the pleasures of writing.