Smit surveyed 103 employed people. He asked them to report which goals they completed and which goals they left unfinished at the close of each day. Before bed they reported on how much these goals had occupied their thoughts.

The incomplete goals intruded their minds more. If participants rated a goal as somewhat unimportant it wasn’t a problem.

This effect applied only to participants who were involved more in their job. Those who were less invested in their jobs were immune to the late night thought intrusions.