A funny Katie moment...

Yesterday, our ward had a young women's spaghetti dinner and silent auction. I didn't make it, but I guess it was pretty good, because Katie really didn't want to leave. Kristi and Haylee were putting the kids in the van when Katie decided that all her screaming and fussing wasn't working well enough. So, she took it to the next level and started kicking, pinching and hitting Haylee as she was helping Katie with her seatbelt.
When they got home, Katie got to have a talk with me. Here's a snippet from the condensed version:

Me: "...Ok, Katie. Now remember that even though you're in trouble, I still love you."
Katie: "I already know that, Daddy! You tell me that all the time. You tell me that too much today! It's already in my head!"
Me: "Katie, be nice or you'll find yourself in more trouble. You need to be nice to people: don't hit, don't punch, don't kick, don't bite, don't pinch. Be nice. Now I want you to put that in your head and remember it, ok?"
Katie: "I already did, Daddy."

So, today, as Katie and Scott were getting in the van to go to a birthday party, a fight broke out between them over who got to carry the present. I stepped in and sent them both to their room. I came in a little while later to talk to them.

Me: "Katie, do you remember the talk we had yesterday about being nice?"
Katie: (sheepishly) "Yes..."
Me: "What did I tell you to remember?"
Katie: "I dunno..."
Me: "What did I tell you to put in your head and remember?"
Katie: "I already don't know! I don't have nothing in my head anymore!"

Needless to say, I had a very difficult time keeping a straight face after hearing that retort. How am I supposed to respond to that?!?