People find it far easier to forgive others for being wrong than being right.

More from Harry Potter and the Half-Blood Prince

• “Greatness inspires envy, envy engenders spite, spite spawns lies.”
• Harry did not usually lie in bed reading his textbooks; that sort of behaviour, as Ron rightly said, was indecent in anybody except Hermione, who was simply weird that way.
• I am a wizard, not a baboon brandishing a stick.
• “I’d love to go with you as friends! Nobody’s ever asked me to a party before, as a friend!”
• “I make mistakes like the next man. In fact, being–forgive me–rather cleverer than most men, my mistakes tend to be correspondingly huger.”
• “You prat Ron, look at the state of her!” “Ginny, don’t call Ron a prat, you’re not the captain of this team—” “Well, you seemed too busy to call him a prat and I thought someone should.”