Dad: "Say daddy!"
Baby: "Mommy!"

Dad: "Come on, say daddy!"
Baby: "Mommy!"

Dad: "Darn it, say daddy!"
Baby: "Darn it, Mommy!"

[Mom comes home and joins the conversation.]
Mom: "Honey, I'm home!"
Baby: "Darn it!"

Mom: "Who taught you that?"
Baby: "Daddy!"
Dad: ...