I worry a lot about deep work (giving sustained attention to hard things that create value). As a professor, deep work is required to produce new results. Therefore, the more I do, the better.
I often envy the schedules of professional writers — like Woody Allen, Neal Stephenson, or Stephen King — who can wake-up, work deeply until they reach their cognitive limit, then rest and recharge until the next day.
The simplicity of this rhythm is satisfying. I could never emulate it, however, because, like most knowledge workers, I’m also saddled with quite a bit of shallow work (task-oriented efforts that do not create much new value). You’d be surprised, for example, how much time you spend after you write an academic paper, formatting it properly for publication (a scene they seemed to skip in A Beautiful Mind).