Psychologies magazine asked novelist Deborah Moggach her favorite part of the writing process:
"The moment a story one is writing comes alive, and the characters start telling you what they're going to do, rather than you imposing it from the top. It's an unmistakable feeling, like the rumble in the bowels of a house when the boiler comes to life...and from that moment the novel lives with you day and night. This is a pretty rare feeling. But bliss when it happens."
The catch, of course, is that you have to write whether or not that's happening. Sometimes the characters are just as lazy or blocked as you are and they refuse to go to work. That's when you have to keep showing up at your desk anyway. After a while, they may join in!
(For tips on how to get yourself and your characters writing, see my book, "Your Writing Coach," published by Nicholas Brealey and available from Amazon and other online and offline booksellers.)