I got to this point last year when I was doing NaNoWriMo, the point where everything is coming together and humming along and looking good. The problem is that I'm still many thousand words from the end. This is the point when I start making things up. And it's usually the point of my greatest inspiration.
I know a lot of writers plan their novels ahead of time. I have read articles in writing magazines about outlining, writing characters backgrounds, laying out every step ahead of time. But I have never done that. I just lack the motivation, I guess.
I once read a quote from J.K. Rowling, in which she said something about her plot not going where she expected, and basically that her characters were doing things she hadn't planned on. To a non-writer this might sound like insanity. I mean, you're the writer - you decide what the characters do. But as a writer, I knew instantly what she meant. Every time I write, my characters end up doing things I don't expect.
Just last night, my main male character's best friend revealed a shocking secret. I stayed up until almost 1 getting it into the computer. He might not have felt as amenable to confessing this morning. And to think I thought he was just a likeable side character.
People will surprise you. Even the fictional ones.