“Social Psychology. Just Think: the Challenges of the Disengaged Mind”, 2014 (; similar):
In 11 studies, we found that participants typically did not enjoy spending 6–15 minutes in a room by themselves with nothing to do but think, that they enjoyed doing mundane external activities much more, and that many preferred to administer electric shocks to themselves instead of being left alone with their thoughts.
Most people seem to prefer to be doing something rather than nothing, even if that something is negative.