One of my all time favorites...

A philosophy professor stood before his class and had some items in front of
him. When the class began, wordlessly he picked up a very large and empty
mayonnaise jar and proceeded to fill it with rocks, rocks about 2" in
diameter.

He then asked the students if the jar was full? They agreed that it was.

So the professor then picked up a box of pebbles and poured them into the
jar. He shook the jar lightly. The pebbles, of course, rolled into the open
areas between the rocks.

He then asked the students again if the jar was full. They agreed it was.
The professor picked up a box of sand and poured it into the jar. Of course,
the sand filled up everything else.

He then asked once more if the jar was full. The students responded with an
unanimous -- yes.

The professor then produced two cans of beer from under the table and
proceeded to pour their entire contents into the jar -- effectively filling
the empty space between the sand.

The students laughed.

"Now," said the professor, as the laughter subsided, "I want you to
recognize that this jar represents your life. The rocks are the important
things - your family, your partner, your health, your children--things that
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, your car. The sand is everything else. The small stuff."

"If you put the sand into the jar first," he continued there is no room for
the pebbles or the rocks. The same goes for your 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. Play with your children. Take time to get medical checkups.
Take your partner out dancing. There will always be time to go to work,
clean the house, give a dinner party and fix the disposal.

"Take care of the rocks first -- the things that really matter. Set your
priorities. The rest is just sand."

One of the students raised her hand and inquired what the beer represented.

The professor smiled. "I'm glad you asked. It just goes to show you that no
matter how full your life may seem, There's always room for a couple of
beers."