Managing Your Time! This story says it best.  I got it from one of the e-mail lists I'm on.

I was reading about an teacher of a time management class.  On the first day of class he was teaching his students and to make his point he used an illustration that the they wouldn't easily forget.  Hopefully you'll never forget it either.  As the teacher stood in front of the class of high-powered overachievers he said, "Okay, we're going to have a pop quiz." Then he pulled out a large jar and put it on his desk. Then he pulled out a bag full of golf ball sized rocks and put them into the jar.  When he put in the last rock the jar was filled to the top, he asked, "Is this jar full?" The class said, "Yes." Then he asked, "Is it really?" He reached under the desk and pulled out a bag of gravel and dumped some gravel in and shook the jar causing pieces of gravel to work themselves down into the spaces between the big rocks.  Then he smiled and asked the group  once more, "Is the jar full now?" By this time the class was  onto him. "No!" one of them answered. "Good!" he replied. And he reached under the desk and got a bag of sand.  He started dumping the sand in and it went into all the spaces left between the rocks and the gravel. Once more he asked the question, "Is this jar full now?" - "Probably not!" said the class. Once again he said, "Good!" Then he grabbed a pitcher of water and poured it in to the jar until it  was full. Then he looked up at the class and asked, "What is the point of this demonstration?"  One student replied "No matter how full your schedule is, if you really try, you can always fit something more into your schedule!" "No," the teacher said, "The truth this illustration teaches us is that if you don't put the big rocks in first, you'll never get them in at all." 

The point of this letter is that the "Big Rocks" of Life have to be given priority. What are the big rocks in your life?  Spending time with your family?  Your relationship with God?  Your education?

No man ever sat on his death bed wishing he'd put in more time at the office or worked harder on some project, they always wish they had spent another day with their kids, or another weekend with their wife, or that they told their family how much he loved them and what they really ment to him. So remember to put the big rocks in first or you'll never get them in at all.