I write stories for fun. Let me tell you, I have very little control over the characters. Once I create them, and start them off, I really am just along for the ride, chronicling the adventures. Occasionally a minor character will take over the story, or someone who should be the main character turns out to be totally unimportant. Maybe real writers don't work like that, but I find it fun! Almost as much fun as reading, and sometimes more.
Hence ... cometh the muse .
I remember John Denver saying about "Rocky Mountain High" and "Calypso" that they came, all of a piece, in about 20 minutes. He had no idea where it came from ... he just received it and wrote it down. Of course, he was on a ski lift in the Rockies for the first one and actually on Jacque Coustos (Sp?) ship at sea for the second. There were others as well. Example only.