The Zeigenark Effect was outlined by early-twentieth century psychologist Bluma Zeigenark, who proposed and tested with experimentation that an incomplete task would dominate a certain level of cognitive attention, even when not focusing on said task. Obligations left unresolved, therefore are postulated to prevent one from accomplishing other, unrelated tasks. The remaining cognitive resources used for an incomplete task were termed the Zeigenark effect.
Tasks that are left incomplete, as you may know are virtually endless and most people tend to never run out of things they know they should be doing or will need to finish.
There is a way, however to ensure that the Zeigenark Effect is reduced, even without completing a task, giving one the ability to ignore the task to focus on other aspects of life. The method would be, as one comes to a close on their allotted time for concentration on said task, quickly produce a plan for how the incomplete task may later be completed, best done in writing. Through this method, one may free up cognitive resources to concentrate on other avenues of life and gain an edge whence returning to said incomplete task. If tasks are relatively uncomplicated but are many, one may decide to simply maintain a list of tasks, such that one need not use cognitive resources to stay on track.