Starting but not finishing too many projects puts a person at risk of the so-called Zeigarnik effect, named for Bluma Zeigarnik, a Russian psychiatrist who, in the 1920s, discovered that people are better at remembering unfinished tasks than completed ones. Unfinished items that we’ve left hanging are like cognitive itches. (Zeigarnik first made this observation watching servers remember detailed meal orders at a restaurant only as long as the order was in process.)