“Pay attention to your enemies, for they are the first to discover your mistakes.” Antisthenes
So, doesn’t that in some odd way make your enemies your friends? That is, I guess, the sentiment from another quote, one of my favorites, from Oscar Wilde: “True friends stab you in the front.”
All that to say what I guess is generally known – separating friends from enemies is tricky business, and requires occasional reconsideration.
It occurs to me... 