My soon to be 18 year old son, who is a great kid in almost every way, cannot take "no" for an answer. He is a good student, and everyone who meets him tells me how polite he is. I have been doing my best not to micromanage him, however some things are just totally out of the question, such as a coed sleepover ("in separate rooms") after a school dance, and I told him absolutely not. He continues to badger, asking "why not", etc, until I explode on him. (I know, I shouldn't, but he knows how to push every button). I want to be able to have an adult to adult conversation with him, but he needs to know that no is a complete sentence, and I do not have to justify it to him.