I usually write from the hip, because past experience has taught me that plotting destroys any urge to tell the story. Like talking about the story with someone. The minute I've told the story, in however abbreviated a form, the minute I know what the beginning-to-end is and put it down in any form whatsoever, I'm done. I'm satisfied that the tale's told.
However, this story has me approaching things from a less... "I really wanna tell this cool story" perspective and more from a "how do I write a saleable novel" perspective. Which has led to plotting things out, but it's been almost no fun to write after a certain point. Which is probably the other reason I've stopped writing it. It's no fun anymore.