"Pay attention to your enemies, for they are the first to discover your mistakes."
permalink source: Antisthenes, Greek philosopher"Love your enemies, for they tell you your faults."
permalink source: Benjamin Franklin, US statesman, diplomat, inventor, printerSome people make enemies instead of friends because it is less trouble.
permalink source: E.C. McKenzieFriends may come and go, but enemies accumulate.
permalink source: David Belasic