Just some Jung.
Someone asked me about the difference between an introvert and extravert, finally i just pulled out the book, found where Jung explained it, and read it to him myself. Anyway, i was so interested, i read the entire section. Jung is something you can't just put down so easily.
The book is "Psychological Types" with the translation revised by RFC Hull.
Extraverted Irrational Types (ESTP/ESFP/ENTP/ENFP)
To the rational mind it might even seem that such a hodge-podge of accidentals hardly deserves the name "psychology" at all. The irrational type ripostes with an equally contemptuous opinion of his opposite number: he sees him as something only half-alive, whose sole aim is to fasten the fetters of reason on everything living and strangle it with judgements.
Introverted Rational Types (ISTP/INTP/ISFP/INFP)
Little wonder, therefore, that it is precisely in the present epoch, and particularly in those movements which are somewhat ahead of the time, that the subjective factor reveals itself in exaggerated, tasteless forms of expression bordering on caricature. I refer to the art of the present day.
par 665 Introverted Irrational Types (ISTJ/ISFJ/INTJ/INFJ)
From an extraverted and rationalistic standpoint, these types are indeed the most useless of men. But, viewed from a higher standpoint, they are living evidence that this rich and varied world with its overflowing and intoxicating life is not purely external, but also exists within. These types are admittedly one-sided specimens of nature, but they are an object-lesson for the man who refuses to be blinded by the intellectual fashion of the day. In their own way, they are educators and promoters of culture. Their life teaches more than their words. From their lives, and not least from their greatest fault--their inability to communicate--we may understand one of the greatest errors of our civilization, that is, the superstitious belief in verbal statements, the boundless overestimation of instruction by means of words and methods. A child certainly allows himself to be impressed by the grand talk of his parents, but do they really imagine he is educated by it? Actually it is the parents' lives that educate the child-what they add by word and gesture at best serves only to confuse him. The same holds good for the teacher. But we have such a belief in method that, if only the method be good, the practice of it seems to sanctify the teacher. An inferior man is never a good teacher. But he can conceal his pernicious inferiority, which secretly poisons the pupil, behind an excellent method or an equally brilliant gift of gab. Naturally the pupil of riper years desires nothing better than the knowledge of useful methods, because he is already defeated by the general attitude, which believes in the all-conquering method. He has learned that the emptiest head, correctly parroting a method, is the best pupil. His whole environment is an optical demonstration that all success and all happiness are outside, and that only the right method is needed to attain the haven of one's desires. Or does, perchance, the life of his religious instructor demonstrate the happiness which radiates from the treasure of the inner vision? The irrational introverted types are certainly no teachers of a more perfect humanity; they lack reason and the ethics of reason. But their lives teach the other possibilities, the interior life which is so painfully wanting in our civilization.
Got to love "pernicious". Heh.