I'm not sure if this exactly what you're talking about, but I think it's important to be able to be content and calm while doing nothing. If not, it's a sign something is off with your mental health.
In very general terms, our brains are pretty good at finding ways to avoid lingering mental issues (trauma, anxiety, etc). You're probably familiar with strategies like alcohol and drugs, but people also use strategies like exercise, work, keeping busy, etc. The goal is the same: keep those pesky thoughts down and avoid them. If you're not doing something, these things bubble up and cause issues.
