Recent job disappointment (i.e. I didn't get a job I was hoping I would) has forced me to think about my dissertation again. I have never said, "I'm not going to do it," but I've had some serious doubts. Part of the problem is that my dissertation feels more like a hobby. It's that craft project that just never gets finished. Every once in a while you find it on the shelf, take it down, spend an hour trying to figure out where you last left off, and then you add a few more rows or stitches. You have good intentions to keep at it, but inevitably things get in the way and then it gets put back on the shelf.
Obviously a dissertation should not resemble an unfinished quilt stuffed that's been stuffed in the closet. Rather than a hobby, it should be central to my life, my work. But it's so easy to get away from, so easy to shelve. When I'm in the midst of it, making some tiny progress, I enjoy it. Or find it satisfying, at least. But then more seemingly pressing demands arise (kids, teaching, housework, TV shows, etc.) and then the energy to get my head back into "the zone" is pretty difficult. It doesn't help that I'm not exactly what you'd call methodical or organized.
There is a book about writing your dissertation that suggests you can finish by working on it for fifteen minutes a day. I've heard some negative feedback on it, but i suspect there is some value to the premise. Fifteen minutes isn't much but it's enough to keep you from getting away from it, from putting it back on the shelf. It's enough to make it a habit instead of a hobby.