Say please, please

At lunch.

Daddy: Pia, can you get the water from the fridge?

Pia: (poker faced, no response. not even looking up from her plate)

Daddy: Pia, could you get the water?

Pia: (no reaction)

Daddy: Peeeeeeeeee-yaaaaaaaaaaaaaaaaah!

Pia: (still poker faced) You must say please.