Take the case of a large number of people who have gathered together for the purpose of carrying out some practical project. If there are two rascals among them, they will recognize each other quickly, as if each wore a similar badge, and they will at once conspire for some selfishness or treachery… It is really curious to see how two such men, especially if they are morally and intellectually inferior, will recognize each other at first sight, with what zeal they will try to become friends, how affably and cheerfully they will rush to greet each other.

Arthur Schopenhauer (1788 – 1860)