One day a professor was giving a lecture to his students about time management. He pulled out a big glass jar full to the brim of large rocks. He looked at the class and asked "Is the jar full?". The class replied "Yes". The professor paused a moment and said "Really?" He then pulled out a bag of pebbles. He carefully poured the pebbles in and slightly rattled the jar, allowing the pebbles to slip through the larger rocks, until they settled at the bottom. Again he asked the students "Is the jar full?" They replied "Yes". Next the professor pulls out a bag of sand and pours it over the rocks and pebbles, filling in all the tiny spaces. The class again thinks the jar is full...until the professor opens a can of Pepsi and pours it in the jar.
He explains that the large rocks represent the things that really matter in our lives-our highest priorities- such as God, family, church, job, etc... The pebbles and sand represent all of the other activities we spend time doing that are of less importance. Point: If you put the pebbles or sand in the jar first, there will be no room to fit all the larger rocks later. But if we prioritize by first filling our lives with what is most important, then we will find room for the other things we enjoy doing.
After thinking this through, one of the students asked "What does the Pepsi represent?" The professor replied..."It just goes to show that there is always room for Pepsi" :)