eat your brocoli
used instead of the phrase "don't ask too many stupid/irrelevant questions and just do as you are told".
a boy, eating brocoli for breakfast, ask his dad:
boy: dad, why do i have to go to class?
dad: because it's fun, James. And, please, because I am in a bad mood since yesterday, having gotten a parking ticket, please eat your brocoli. just pick your things so I can take you to your class.