Long, long ago, when I used to play competitive Magic at tournaments, players would often disagree about things during matches. A judge would be called, and the players would explain what had happened.

Player A: He tried to Incinerate my Imp, and that's illegal.
Player B: I did not try to Incinerate his Imp, I tried to Incinerate his Orc.
Player A: You liar!
Player B: I'm not lying, I blatantly targetted your Orc.
Player A: (angrily) He's bloody lying.
Judge: Failure to agree on reality.

The phrase, "Failure to agree on reality," always made me smile because it was so ridiculous, but it was pretty much exactly accurate.

Five years later, and Mattgreen and I get it all the damn time with Isabel.

Izzy: Where do peas come from Mummy?
Alicey: Peas come out of a pod that grows on a plant.
Izzy: No they don't.

Izzy: I want to wear pink shoes.
Alicey: You haven't got any pink shoes.
Izzy: Yes I have.

Alicey: I have to drive the car home.
Izzy: No you don't.
Alicey: I do, because you can't drive.
Izzy: Yes I can.

Any continuation of these discussions always leads to, "No it doesn't!" "Yes it does!" pantomime ridiculousness. I usually sigh in exasperation, whereas Mattgreen announces, "Failure to agree on reality"! He's spot on.