How's this for an argument ender? Let's say your son, Sam, wants to go to a party and you won't let him. He says "You let Johnny go to a party". You could say that Johnny went to a supervised kiddie party that had cake and ice cream. Fifteen year old Sam wants to go to a frat party that will have kegs of beer and pots of marijuana. You know Sam will keep coming up with more arguments to change your mind before handing you the world's worst parent award and leave you with a headache. So, the next time Sam does this you can say, "How does that change what I just said." It will end the argument, save you from a headache and you get your award much sooner. At least it's worth a try.
