Cupcake Negotiations with a 5 year old

(Otherwise titled "Why child-like irrationality is awesome.")

This is an excerpt from a conversation with my daughter yesterday:

Me: Hey Sydney, Grandma brought over cupcakes, do you want one?
Syd: Okay mom, here's the deal; I'm only going to eat that cupcake if you can promise me that I can watch a movie today.
Me: Well, I can't promise you a movie, but would you still like a cupcake?
Syd: Nope, sorry, can't do that.
Me: Okay, then

(exactly 90 seconds of silence later)

Syd: Mom, do you think I could have a cupcake?