A professor stood before class with items on table in front of him. When class began, he picked up a large glass jar an started to fill it with rocks of about 2 inch in diameter. Then he asked students if the jar was full. All students agreed. Now the professor picked up a box of pebbles and poured them into the jar. He shook the jar slightly, so the pebbles rocked into the empty areas between the rocks. Again he asked students if the jar was full. Again all the students agreed it was. The professor now picked up a box filled with sand and poured into the jar. The sand filled the remaining open areas in the jar. Once again he asked to students if the jar was full. Students respond with 'yes'professor said:"Now, I wasn't all of you to recognize this jar as representation of your life. rocks here represent the important things like  your family, friends, health, children; if everything else was lost jar will still remain full.pebbles are other things that matter like your job, car house. and sand represents all other small stuff in life. now, if you first put sand into jar then her will be no room for pebbles. same goes for your life that means there will be no room left for important things in your life if you spend all your energy on small stuff.pay attention to the things that are critical to your happiness." 
Give important to things that really matters. Set priorities. Rest is just sand. 