If you’re “pleased as Punch,” you’re extremely pleased, delighted, self-satisfied.
The expression derives from the puppet character, Mr. Punch (Polichinello) in the Punch and Judy puppet shows that originated in the 1500s in Italian Commedia dell’arte.
The show began in Britain in the 1600s. The Diary of Samuel Pepys has an entry from 1666 that shows the popularity of the show: “I with my wife… by coach to Moorefields, and there saw ‘Polichinello,’ which pleases me mightily.”
Punch and Judy shows used to be popular summer-time entertainments on British beaches, but are not performed so much now, since they’re seen as politically incorrect. But the words “politically incorrect” don’t even begin to describe the so-called entertainment. The main character, Punch, is a wife-beating serial killer. He beats his baby to death, as well as his wife, a policeman, and various other characters.
The Punch character is depicted as grotesque, self-satisfied, and delighted with his evil deeds, squawking “That’s the way to do it!” whenever he dispatches another victim. He’s happy to outwit every figure of authority.
“As pleased as Punch” is now the most common form of the expression, but when the term was coined it was just as usual to say, “as proud as Punch.” Charles Dickens used both terms in his novels. For example, in David Copperfield (1850): “I am as proud as Punch to think that I once had the honour of being connected with your family.” In Hard Times (1854): “When Sissy got into the school here.… her father was as pleased as Punch.”
As the play fades into history, the expression is doing likewise. And I must say that I’m as pleased as Punch that that is happening.