"It is one of the most common and generally accepted superstitions to attribute some particular leading quality to every man--to say of him that he is kind, wicked, foolish, energetic, or dull. This is wrong. We may say of a man that he is more frequently kind than cruel, wise than foolish, energetic than apathetic, or vice versa--but it could never be true to say of a man that he is kind or wise, and of another that he is wicked or foolish. Yet this is our method of classifying mankind and a very false method it is. Men are like rivers. The water is alike in all of them; but every river is narrow in some places and wide in others; here swift and there sluggish, here clear and there turbid; cold in winter and warm in summer. The same may be said of men. Every man bears within himself the germs of every human quality, displaying all in turn; and a man can often seem unlike himself--yet he still remains the same man."
Leo Tolstoy, Resurrection, p. 190