Working Late at the Office

As we know and maybe you've heard said, there has never been an epitaph saying, "I wish I spent more time at the office." Most of us would agree that no sane person, leaving this life, regrets that more time should have been spent at work.

OK; that's not hard to grasp and seems pretty much self-evident. But then, why, why do so many (intelligent and sane) people live as if it will be a great regret that they didn't spend more time at work? I don't get it.