"It's Daddy's fault!"

Katie is sitting on the couch with Daddy and announces, "Daddy, it's your fault." Daddy then replies, "What is my fault?" To which Katie says, "It's your fault!" After a few of these exchanges, Daddy switches tactics and asks, "Why is it my fault?" Katie's reply? (Picture the devilish grin that accompanies this ...) "Because it's not *my* fault!"