It happens to me all of the time. I am writing and one of the people I show my first drafts to are reading and suggest that something isn’t clear, or could be different. While they sit there I start to rewrite a section that the reader had a concern with and the next thing I know, something completely different is flowing and I am typing like a word addict. Some say I get this odd look on my face, like I am on another planet, until I am finished.