Often time, when a man matures, he questions his existence here on earth. His introspection and retrospection about his living create an immediate desire for him to find his purpose. It is quite a common untold thinking that every man ravels to himself, either for evil or for good, this sudden self-questioning leaves a man exposed to the whims of luck, distraction, failure, shame, guilt and other ramification of societal problems or personal challenges.

As an observer of life, I have notice people wishing to create their legacies, a will to add impact to the life of others close to them. This leads to one finding his purpose in life. Some set attainable mission to achieve in different areas of their life as purpose finding is never illogical.
In the olden times, when a man is born, there are some responsibilities that have been passed to him especially from his father to learn the art of fighting, manipulation, politics, religion or sourcing for food etc. After all lesson, it is left for the same man to use his learned skill, education or training to achieve a greater purpose for himself, Thus, he create this desire simply because he might aim for the top or he aim to use his assets to benefit himself, his generation, his society or his future.

Psychologically, what pushes one to create the sudden sense for purpose is as a result of the development of the whole body system. If the body can grow, the mind experiences growth, the soul acquire and grow, the spirit seek to grow and the reason for survival grow as well, this explain why biological difference which is based on stages of the growth of human create a different levels of thinking for individuals.
Diving further to purpose, the need for improvement in oneself craves the inner sense of purpose, if one can seek to improve, he needs a moral skill, discipline, as discipline is the first tool requires for fulfilling ones purpose as it is the same requirement necessary for self improvement. The urge to improve is what develops the urge to find greater meaning in life.

Another angle for the reason for purpose finding is the attitude that comes when it involve facing challenges, those who seek to move out of their comfort zone are those who find purposes for themselves. Purpose comes from the will to challenges oneself for greatness. Even many great men from ancient history have faced tremendous challenges that out pour their passion for achieving greatness.
Finally, the sense of purpose is deep, intense and an overwhelming feeling to fulfill his needs through many steps applicable and available to oneself. Our body, soul and spirit have needs, and then the urge to live for a greater purpose is inevitably one of those needs.