There are only two people who can tell you the truth about yourself - an enemy who has lost his temper and a friend who loves you dearly.
Observe your enemies, for they first find out your faults.
Quarrels often arise in marriages when the bridal gifts are excessive.
Not to unlearn what you have learned is the most necessary kind of learning.
We must not contradict, but instruct him that contradicts us; for a madman is not cured by another running mad also.
The most necessary learning is that which unlearns evil.