In 1922, a study was published that showed that waiters only remembered patrons and their orders while they were actively in the middle of ordering and delivering the food. After the food was delivered and payment made, they would forget the details of the interaction.
The Gottman Institute has used the Zeigarnik Effect to create a framework for processing a regrettable incident between people. They say it shows the importance of "completing" something so that the mind (and heart) can move on.
Below are the details about how to have a productive closure conversation.
https://www.thriveglobal.com/stories/47732-ex-wants-more-relationship-closure-asking-for-a-friend?utm_source=Newsletter_General&utm_medium=Thrive&mc_cid=003868e252&mc_eid=7054af1a50