I guess not all teens go through it then. I don't even know if my 18 year old brother did but I know my other one did. I can remember he start getting snotty and my mother would point it out to him and he say "Oh sorry mom, I didn't know I was doing it" and he stop.
Shows how unaware they are when they do it and the parents have to point it out to them. But I know not all of them stop and say "oh sorry mom" and then stop. My brother was just mature for his age. He was already an adult before he turned 18 lol.