Nothing splendid was ever created in cold blood. Heat is required to forge anything. Every great accomplishment is the story of a flaming heart.
I'm pretty Sicilian if I've been crossed. I don't seek revenge, but I never forget. And I make it hard to repair, which is not a great quality because if people held me to that standard, no one would be around me - ever.
I think it's a novelty for cartoon characters to cross over into another strip or panel occasionally.