Yeah, me neither.
As it turns out, that feeling of stress and anxiety you get from unfinished jobs--even not-so-important ones--has a specific name in psychology. It's known as the Zeigarnik Effect, after psychologist Bluma Zeigarnik, who was inspired to conduct research after her professor realized that restaurant workers tended to remember orders being worked on but not ones that were finished.
In essence, the Zeigarnik Effect says that your brain will remember and want to come back to unfinished work more than problems you've already handled. On the one hand, this is because the unfinished job is novel and fun for the brain, because you've got a puzzle to solve. On the other hand, not knowing the answer can generate some anxiety.
Storytellers know this well. It's why they try super hard to end chapters, books or movies in a series on some kind of cliffhanger, and why great lecturers end sessions with an intriguing question to think about for the next class. It's not so much that you want to know exactly what happens next or that a specific answer matters, so much as your brain is just trying to wrap things up with any answer.
The Zeigarnik Effect demonstrates three big ideas for leaders:
1. Admit that you're not totally objective about what you have to do (no one is).
Even if you consciously tell yourself that a piece of work is superficially inconsequential or worth procrastinating about, subconscious biases you've already made in your brain can counter that idea hard and keep the problem nagging you. You can rewrite those biases by telling yourself a new truth over and over, but this takes time.
So whenever possible, if there are little problems or tasks you've been unable to do, even if it's just doing the dishes or finally sending someone a calendar invite, schedule them and knock them out. Don't let them pile up. Your brain will stop bringing these tasks to the fore and robbing you of focus once they're out of the way. And if an "unimportant" job won't leave your mind, it might be worth it to allow yourself the "detour" to finish it.
2. Create a plan.
Secondly, as John Tierney and Roy Baumeister explore in Willpower: Rediscovering the Greatest Human Strength, a critical caveat to the Zeigarnik Effect is that simply having a clear plan for how to finish the task is effective for getting the brain to let go of the problem. Because the brain knows exactly how you'll tackle the work, it stops seeing the job as important enough to keep ruminating over and puts it in the "done" category, even though you technically still have to act on the plan you've created.
So if you have a job you can't complete for a while, at least come up with the steps you'll take to get the work done--the how, what, when and where all should be laid out. From there, do everything you can to ensure the follow-through of those steps, whether that's finding an accountability buddy, bringing supplies into the office or just getting adequate rest.
3. Get real about your priorities.
Lastly, get out of the habit of putting non-priorities on your to-do list in the first place. The idea is that you want to emphasize to your brain that you really only have a handful of items that deserve rumination, and to take some control over how many things are on your plate to stress over. Two to three big items for the day is usually plenty.
The Zeigarnik Effect shows how small items can get in the way of larger productivity. It also demonstrates why it's so important for you to understand your limits, have clear goals and not to bite off more than you can chew. Simplicity is strength and a stress buster, so don't let yourself or anyone else make your day more complicated than it has to be.