First I'll respond to this "Managers can sit for hours at a time if they want-but it's their job to see that no one else ever does" what really got my intention was this part, because most manager don't do anything until these days.
Second I'll share about an anecdote about work. One of my interesting job was driving a truck from state to state; it didn't even last for six month until I realized it isn't an easy job. Meanwhile, it has both a negative and positive side. First, when you're new to trucks they'll tell there is big money to be made and that never comes out to be true,but the positive side is being on the road and enjoying the view.