So, the Zeigarnik effect makes you want to complete what you started right?
What if you have one of those personalities that have no trouble starting new things, but have trouble finishing things? It makes sense that the Zeigarnik effect now works against you. Remember, completing something makes you immediately forget the details of what it was that you just completed. Thus it stands to reason that not completing things makes you feel that there are still so many things to do, loaded will many details. You did not get any closure so to speak. Ever had that restless feeling that you still had so much to do?