Sometimes I stop working on writing projects. This could be
a slight pause or a complete halt.
Why pause?
It gives me time to solve a plot problem.
It gives me time to improve my craft so that I may complete the story.
Another, more interesting or promising, writing project has caught my eye.
Why halt?
I’ve lost interest in the story for some reason. There are many decisions to be made while I write. What point of view will I use—first or third person? Whose story is this? What plot will I follow? My lack of interest may be the result of a wrong decision.
My inability to successfully answer the question: How will I market this manuscript and to whom? I’m building a career. If a project won’t further this career then I stop working on it.
Am I disappointed when I have to abandon a project?
Yes, somewhat. However, I firmly believe that no writing time is wasted. Each sentence, paragraph, and scene I write develop my skill. And the words aren't lost. I can and have mined uncompleted projects to assemble new ones.