Never compete with someone who has nothing to lose.

No one heals himself by wounding another.

Never do an enemy a small injury.

Never injure a friend, even in jest.

Never offend an enemy in a small way.

Never question another man's motive. His wisdom, yes, but not his motives.

Never take counsel of your fears.

Never soar aloft on an enemy's pinions.

Never pick a fight with someone you're not sure you can defeat.

Never argue with an artist.

Never whine, never complain, never try to justify yourself.

Never complain, never explain. Resist the temptation to defend yourself or make excuses.

Never test another man by your own weakness.

Never build your emotional life on the weaknesses of others.