An expert on the subject of time management was speaking to a group of business students and, to drive home a point, used an illustration those students will probably never forget. As this man stood in front of the group of high-powered over-achievers he said, "Okay, time for a quiz." Then he pulled out a one-gallon, wide-mouthed Mason jar and set it on a table in front of him. Then he produced about a dozen fist-sized rocks and carefully placed them, one at a time, into the jar. When the jar was filled to the top and no more rocks would fit inside, he asked, "Is this jar full?"

Everyone in th…