There are three kinds of intelligence: one kind understands things for itself, the other appreciates what others can understand, the third understands neither for itself nor through others. This first kind is excellent, the second good, and the third kind useless.
Niccolo MachiavelliPeople should either be caressed or crushed. If you do them minor damage they will get their revenge; but if you cripple them there is nothing they can do. If you need to injure someone, do it in such a way that you do not have to fear their vengeance.
Niccolo MachiavelliI consider it a mark of great prudence in a man to abstain from threats or any contemptuous expressions, for neither of these weaken the enemy, but threats make him more cautious, and the other excites his hatred, and a desire to revenge himself.
Niccolo Machiavelli