Fuck you, but without using the word "fuck".
Son: "Mom, I'm really hungry right now, I want some more food."
Mom (Karen): "You need to share with your little sister."
Son: "But she has already eaten three bowls of it already!"
Mom: "She's younger than you, and besides: THE WORLD DOESN'T REVOLVE AROUND YOU!!!11!!"
Son: "Yeah, FUCK YOU TOO then!"