I first realized this concept on much simpler level. In college, my older friend and I were slowing waking up after a very successful party. There was one beer left. And I said, "That would perfect if we had zero beer left". He replied, "No, one beer is perfect. It means everyone got enough. If there were zero then that means someone could have tried to get a beer after we ran out. With one left, we know that everyone got exactly as much as they wanted."