"I distrust plot for two reasons: first, because our lives are largely plotless, even when you add in all our reasonable precautions and careful planning; and second, because I believe plotting and the spontenaity of real creation aren't compatible."
I'll let you in on a little secret. I have never started any work with any idea whatsoever how it was going to end from the most concise of short stories, to my 110,000 word novel. Hell, sometimes where my blog entries end up is a surprise to me. I think that in any good story, the characters dictate where it goes, and the writer merely watches and takes notes.
That isn't to say that planning is a bad thing. I've outlined anywhere from a few to several chapters ahead for each of my four novels to give myself a sense of direction and an idea of where things might end up, but those outlines have probably wound up being about 50% accurate at best in the end. (A small exception is Skankarella, but since that is an adaptation of another work (Cinderella), there was only so much room for divergence. Even so, the initial chapter outline of the entire novel was around 18 chapters. The finished product is 32 chapters and two characters changed gender over the course of writing it.)
Sometimes the divergence is greater than others. I've had instances where I've said "okay, they will get here eventually, but they need to go here, here, and here first" (hence often adding chapters). I've also stricken entire chapters from the story, or devalued their importance greatly. (A prime example of that was in The Chosen where upon writing what I thought would be the ending, I realized that the characters had so much more to address and take care of and made it the middleing.)
It's a pretty good antidote for the dreaded writers' block, an ailment from which I have never really suffered. (Look at me, all cocky.) If you're dictating where the story goes, it can be easy to get stuck, but if you have a good sense for who your characters are, they're never going to sit around and do nothing.