As a rule, I think they are quite impossible. Geniuses talk so much, don't they? Such a bad habit! And they are always thinking about themselves, when I want them to be thinking about me.
The greatest thing by far is to be a master of metaphor; it is the one thing that cannot be learned from others; and it is also a sign of genius, since a good metaphor implies an intuitive perception of the similarity of the dissimilar.