Some people like piecing, some like quilting, others like binding. It is normal for one person to prefer one part of the process over another. Can you find someone to finish them for you? Maybe you could barter.
As for the WHY - I watched Oprah the other day when she had Tony Robbinson on. Not that I am a big fan, but the subject interested me. They talked about the story WE TELL OURSELVES. For example, part of my story (I had to admit) is that nothing matters because I don't matter. At a conscious level I know that is not true, but subconsiously...that's another story. You need to find out what you are telling yourself. Trust me, you'll know whether you are speaking the truth. (You can only kid yourself for so long) Once you figure out what the negative story is, then you can change it to a more positive approach. Try it and see.