"Du hast ein vogel."
You have a bird.
This is one way Germans tell someone they're crazy.
For writers, it may actually be sort of true!
I call it the Magpie of Ideas. When you're working on a story, it's that part of your brain that likes to come up with all these shiny new ideas. And then it whispers to you, saying "hey, look at this!" over and over again. It tries to draw you away, because it wants to chase that cool new thing. Just like a real magpie, it's fascinated by the shiny.
And if you listen to it, that's when it turns into a whole damn flock. Every new story generates a new idea, with another magpie. Before you know it you've got 20 first chapters and a hundred ideas squawking at you, vying for your very limited writer's attention span.
Don't listen to the Magpie of Ideas. Keep it locked in its cage and throw a mental blanket over it. You'll still hear its muffled cries for attention, but you have to ignore it.
Ideas are easy. Writing is hard. Don't feed the birds.