Authors: Your Characters are Defined by the Actions they Take

I've never been big on plotting and planning. I know the major points of my story, and I know the main details about my characters, but beyond that, I just. can't. plot. any. further. I have to dive into the story and get going. It's like the story details "reveal" themselves to me as I get further and further (this is why I totally get what E.L. Doctorow said: “Writing is like driving at night in the fog. You can only see as far as your headlights, but you can make the whole trip that way.”)...