Now and then I finish early and think, tonight I'll actually do something else. Then I look up and I've filled the gap with more work, every single time. I've never once managed to turn spare time into rest or anything else. Work just quietly expands to swallow whatever I give it.
More people experience this than they realize.
Any free time you get just fills up with more work.
If this sounds familiar, the Library can help you find the bigger picture.