Reason for stopping: I'm really awfully, awfully tired, and I've gotten to hesitation point, although not a new scene. (Another character just walked into the room.)
I should probably try to finish the scene. But I think it would be saner of me to goof off a little now, answer some email, and take another crack at this tonight after a nap, a walk, and dinner.
I'm on page 982, and I have 1005 pages of manuscript. Good god damn, this is a pile of paper. It's now more or less officially twice as long as anything else I've ever written.