A professor stood before his philosophy class and had some items in front of him. When the class began, he wordlessly picked up an empty mayonnaise jar and proceeded to fill it with golf balls. He then asked the students if the jar was full. They agreed that it was.
The professor then picked up a box of pebbles and poured them into the jar. He shook the jar lightly and the pebbles rolled into the open areas between the golf balls. He then asked the students if the jar was full, and again they agreed.
The professor next picked up a box of sand and poured it into the jar. Of course, the sand filled up the remaining spaces. He asked once more if the jar was full and the students responded with a unanimous 'yes.'
"Now," said the professor, "I want you to recognize that this jar represents your life. The golf balls are the important things, your family, your children, your health, your friends and your favorite passions. If everything else was lost and only they remained, your life would still be full. The pebbles are the other things that matter like your job, your house and your car. The sand is everything else, the small stuff. If you were to put the sand into the jar first, there is no room for the pebbles or the golf balls. The same goes for life. If you spend all your time and energy on the small stuff you will never have room for the things that are important to you. Pay attention to the things that are critical to your happiness. Take care of the golf balls first, the things that really matter. Set your priorities. The rest is just sand."