Whats demand gets more priority?

There is a huge change in the people's demand with time. When a person is in a stage of childhood, always he wants to fulfill his needs. Not to follow the others even brother or sister. Gradually, when he crosses his childhood, then he feels the needs of others slightly. But then he still gets priority on his own needs. When he is full grown, he slowly avoids his needs and wants to fulfill the needs of others. Because then he realizes that anyone has ever given up his own needs to fulfill his needs. And now he is slowly reaching the age of that person. Gradually there will be a time when there will be no value of his demand. Because he will be always busy to fulfil the others demands.