Maybe some, but not all. An old but concrete example: Andy Grove, in High Output Management, describes a fairly typical 8 to 5 day in which he works until he's

Maybe some, but not all. An old but concrete example: Andy Grove, in High Output Management, describes a fairly typical 8 to 5 day in which he works until he's tired, with level of fatigue vs level of "doneness" being the deciding factor of when he ends his day.