My Process? What Process?

In December, I was a guest on The 25th Hour Radio Show. (here’s the link if you’d like to listen in. The interview runs around 15 minutes: )
One of the questions they asked was a common one that I get as a writer: Do you have a plot in mind, or do you just make the story up as you go along?
As part of my book proposal, I have to have a pre-planned synopsis. I have characters sketched out, a basic plot complete with start, middle, and end, and conflict is present. My editor okays it, I start writing … and then magic happens.
The characters take over the story and begin to tell me what really happened.
For non-writers, that may seem unbelievable, but trust me–the characters can surprise you at the oddest times. In THE SUMMER PLACE, I tried for several chapters to get the characters to sleep together, and they kept refusing. Can you imagine? I shook my finger at them, threatened to send them to bed (alone) without dessert, threatened to rewrite the beginning.
Nothing worked.
They needed to get to know each other better first, they told me.
Have you ever heard the like?
And, lest you think that was a fluke, I’ll admit that it has happened again.
I’m 75,000 words deep into a 85,000 word manuscript that’s due to my editor February. On a whim a couple of days ago, I peeked at the synopsis I turned in months ago.
Is that what was supposed to happen in this book? It certainly wasn’t the story the characters told me, and their story is sooooo much better than the one I dreamed up before I knew them so well.
I’ve heard that to not decide is to decide. I guess to not have a process can be a process.
I just hope my editor is as thrilled with the outcome of the non-process as I am.

So how about you? What are the things in life that you probably should have a plan for but find it much more rewarding to let whatever will happen?