A teacher stood before the class, and had some items on the podium. When class began, the teacher picked up a large empty pickle jar, and proceeded to fill it with medium sized rocks (about 2" in diameter).
The teacher then asked the students if the jar was full. The few who were paying attention, agreed that it was full.
So the teacher then picked up a box of pebbles (about 1/4" in diameter), and poured them into the jar and shook the jar lightly. The pebbles, of course, rolled into the open areas between the rocks. The students laughed as they could see where this was heading.
The teacher then picked up a box of sand, and poured it into the jar. Of course, the sand filled up every nook and cranny, so now it really was full.
"Now," said the teacher, "I want you to recognize that this jar is analogous to your time. Note there is a limited capacity to the space in the jar.
The rocks are the important things - your health, your parents, your spouse, your children, and your education - anything that is so important to you that if it were lost or missed, you would be devistated or it would change your life for the worse.
The pebbles are the other things that are important, but are not irreplacable, like your job, your house, and your car.
The sand is everything else - the small stuff - like your hobbies, social clubs, parties, movies, playing video games, cool clothes, music, travel, and socializing with friends.
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 really are important.
Pay attention to the things that are critical to your happiness, to your health, and to your future.
Do your best when getting your education. Visit your parents. Take time to get eat right and exercise. Get regular medical checkups.
There will always be time to socialize with your friends, to play video games, to watch TV, to go shopping, to throw a party, etc.
Take care of the rocks first - the things that really matter, then the pebbles. Don't let the sand push out what really matters.
Set your priorities and remember when you make a choice to do one activity, it means you are deciding not to do all the other possible activities you could have done instead. And also remember that some opportunities only come around once.
(Adapted from a classic analogy - author unknown.)