One of the most widespread superstitions is that every man has his own special definite qualities: that he is kind, cruel, wise, stupid, energetic, apathetic, and so on. Men are not like that. We may say of a man that he is more often kind than cruel, more often wise than stupid, more often energetic than apathetic, or the reverse; but it would not be true to say of one man that he is kind and wise, of another that he is bad and stupid. And yet we always classify mankind in this way. And this is false. Men are like rivers: the water is the same in one and all; but every river is narrow here, more rapid there, here slower, there broader, now clear, now dull, now cold, now warm. It is the same with men. Every man bears in himself the germs of every human quality; but sometimes one quality manifests itself, sometimes another, and the man often becomes unlike himself, while still remaining the same man.

Leo Tolstoy (1828 – 1910)