Rage is exciting, but leaves me confused and exhausted.
Opportunity knocks, but doesn't always answer to its name.
Weakness is a better teacher than strength. Weakness must learn to understand the obstacles that strength brushes aside.
Reading about ethics is about as likely to improve one's behavior as reading about sports is to make one into an athlete.
Boredom is the only sure cure for neurosis.
Lead the reader toward the thought, then stop a little short.