You need a nap
The greatest cop-out in the parent/grownup world, this phrase is uttered when the adult is not able/willing to address/alleviate a totally legitimate problem or concern that a child is complaining to him about. Even worse is if the adult uses amused/cutesy/sarcastic expressions and/or actions to accompany said invalid statement, such as giving the kid a couple quick pats on the cheek for "dismissive emphasis and finality", giggling while speaking, saying, "You wanna know what I *honestly* think?" beforehand, opining that "somebunny" needs the nap (which of course makes the child all the more upset and humiliated, since this makes it appear to the child that the adult is not even really listening to him or taking what he has to say seriously), etc.
Statement: You need a nap.
What is really meant: I don't have the time/money/authority/inclination to help resolve your problem, and/or the bratty/overbearing person who is mistreating you is related to a "somebody" who is important to our family, and so I don't dare make a scene or try to demand that you be treated better by him. But I'm afraid to be truthful with you about this because I've always promised you that I will protect you and correct any wrongs in your young life, and so if you find out that I was "just saying that" but actually am not always able/willing to help you in every case, you will hate me as a parent and never trust me again. Same thing happened with me and your grandparents when I was little.
What is really meant: I don't have the time/money/authority/inclination to help resolve your problem, and/or the bratty/overbearing person who is mistreating you is related to a "somebody" who is important to our family, and so I don't dare make a scene or try to demand that you be treated better by him. But I'm afraid to be truthful with you about this because I've always promised you that I will protect you and correct any wrongs in your young life, and so if you find out that I was "just saying that" but actually am not always able/willing to help you in every case, you will hate me as a parent and never trust me again. Same thing happened with me and your grandparents when I was little.