"[Creativity] is like driving a car at night. You never see further than your headlights, but you can make the whole trip that way." - E.L. Doctorow
I suppose that's true, and has generally been my [somewhat limited] experience. Of course, sometimes I wish it were different. I sometimes wish I knew exactly where I was headed and that the writing was just a technicality. But each time I think I've got the story mapped out completely in my mind before I sit down to type it out, I find myself taking turns and going down avenues I'd never even imagined on the map. Sometimes I'm as shocked at what my characters say and do as my readers are.
And that, I suppose, is the beauty of the whole thing. If the actual writing were just a technical exercise, simply typing up a story that was already whole, it wouldn't be half as much fun, as rewarding, or as painful. Sure, the roadblocks that send you on these tangential paths are frustrating, but they often bring us to places more incredible than we'd imagined while dreaming the story up in the shower.