My typical take on this is that this represents some kind of personal failing on my part. If I were more disciplined/talented/creative/whatever, then instead of writing dozens of fragments, I'd've (yes, that's a real contraction!) written a book or three and some complete short stories. Instead, all I've got are ... fragments.
Except that's not quite true. In fact, I've written at least seven complete short stories -- ten or eleven if I want to throw in a few that are more-or-less standalone, but really intended as part of a larger work.
But seven -- indisputably, at the very least, seven -- that are entirely self-contained; that begin and end and are, in every proper sense, complete.
All right, that's not all that many given (a) how long I've been writing and (b) how many things I've started. But seven is still a much larger number than zero. I've been talking about this a bit with Level Head, who has been telling me -- though in the kindest, gentlest possible way -- "Will you please SHUT UP about not being able to finish things, because that's NOT TRUE?" And, it's finally sinking into to my thick skull that, hmm, maybe he has a point.
And moreover: what does "how many things I've started" have to do with it at all? Why do I think of unfinished stories as somehow a negative on the ledger sheet, overbalancing the finished ones?
Let's take another example: art.
Now, as many stories I've started and abandoned, the number of drawings I've started has got to dwarf it by at least a few orders of magnitude. I have sketchbooks stuffed with doodles. I've got inked images with no backgrounds, paintings that I stopped half-way through, digital drawings I quit on -- why, just the other night I started painting a sleeve for practice on clothing, and I'll probably never get around to painting the rest of the figure. I've got oodles of incomplete art. Most of it that even I don't like.
Yet I can't remember ever looking at all the drawings and paintings and sketches and inkings I've done, and thinking "I never finish anything when it comes to drawing." Sometimes I look with pleasure on the ones that got to whatever stage they got to, and sometimes I just look at the handful of paintings I did finish. And think "Hey, that's not bad."
Or I cringe. But I sure don't sit there thinking, "Completing three oil paintings doesn't count, because it's outweighed by the thirty thousand sketches that I never made oil paintings of."
Goodness! That would be insane. All those drawings are practice. I couldn't learn how to finish a piece of art without practicing first. And it's not as though any finished work I did would've been much good without practice.
So why don't I see all those unfinished tales as practice, too?