I know this sounds neurotic, and it is, but I believe sometimes people don’t finish things because they don’t want childhood to be over.
If it’s over, you can never get the love you needed. Any love you get today –– adult love –– isn’t sacrificial. Whereas the love of a good parent is balanced near 95-5, the best adult relationship will hover around 50-50.
Of course, you accomplish nothing by not-finishing something. It’s a poor, symbolic surrogate. Not organising your desk has no relationship to your childhood. But if you can’t object in the relevant area, the objection has to express itself somewhere else.
Actually, it’s more than an objection. If you didn’t have the love you needed, it’s a scream of pain, hurt, resentment, and fury. And fear. You won’t make it. You have to have it, and the door cannot be closed. Your chance for that love cannot be over. So you do things that mark you as still child-ish, and not finishing things can be among them. See? It’s not over. There’s still a chance, and you’re okay.
Logically, the way out of this dead end is to admit it’s over and face reality. You’re okay; you got through it; here you are. You’ve been kidding yourself –– no one else thinks you’re still a child. It’s been delusional.
But knowledge doesn’t change a determined unconscious. You may need to spend some time listening to the misery and fear, or even the tantrum. Maybe you were that scared. Maybe you would have panicked without the hope for more love.
Treat yourself like a rescue animal you’re adopting. Be patient and steady. If magical hope was all you had to hold onto in childhood, then it’s your (parental) job now to provide real support, Even a wounded creature will give up useless symbols when they have the real thing.