Telling jokes

So this is the difference between a 6 year old telling a 'knock-knock' joke and a 3 year old doing the same.

Kat: "Knock-knock"
Me: "Who's there?"
Kat: "Boo"
Me: "Boo who?"
Kat: "Please don't cry!"

Now, the little girl tries

Chloe: "Knock-knock!"
Me: "Who's there?"
Chloe: "It's me, Chloe! Hahahaha! Isn't it funny, Mommy?"