A case for the Third Universal Cardinal Rule of Thumb: Never
   be absolute, unless absolutely necessary:
   A linguistics professor was lecturing to his class one day. "In
   English," he said, "A double negative forms a positive. In some
   languages, though, such as Russian, a double negative is still a
   negative. However, there is no language wherein a double positive can
   form a negative."
   A voice from the back of the room piped up, "Yeah, right."