When class began, wordlessly he picked up a large 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.  "Now," said the
professor, "I want you to recognize that this is your life.  The rocks
are the important things - your family, your partner, your health,
your children - anything that is so important to you that if it were
lost, you would be nearly destroyed.  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, there is no room for the
pebbles or the rocks.  The same goes for your life.  If you spend
all your energy and time 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."