The words "many are called, but few are chosen" are singularly appropriate here, for the development of personality from the germ-state to full consciousness is at once a charisma and a curse, because its first fruit is the conscious and unavoidable segregation of the single individual from the undifferentiated and unconscious herd. This means isolation, and there is no more comforting word for it. Neither family nor society nor position can save him from this fate, nor yet the most successful adaptation to his environment, however smoothly he fits in. The development of personality is a favour that must be paid for dearly. But the people who talk most loudly about developing their personalities are the very ones who are least mindful of the results, which are such as to frighten away all weaker spirits.
Yet the development of personality means more than just the fear of hatching forth monsters, or of isolation. It also means fidelity to the law of one's own being.
But a man can make a moral decision to go his own way only if he holds that way to be the best. If any other way were held to be better, then he would live and develop that other personality instead of his own. The other ways are conventionalities of a moral, social, political, philosophical, or religious nature. The fact that the conventions always flourish in one form or another only proves that the vast majority of mankind do not choose their own way, but convention, and consequently develop not themselves but a method and a collective mode of life at the cost of their own wholeness.
To develop one's personality is indeed an unpopular undertaking, a deviation that is highly uncongenial to the herd… Small wonder, then, that from earliest times only the chosen few have embarked upon this strange adventure. Had they all been fools, we could safely dismiss them as… mentally "private" persons who have no claim on our interest. But, unfortunately, these personalities are as a rule the legendary heros of mankind, the very ones who are looked up to, loved, and worshipped, the true sons of God whose names perish not. They are the flower and the fruit, the ever fertile seeds of the tree of humanity.
Excerpt taken from: Collected Works of C.G. Jung, Volume 17: Development of Personality.