These years are important ones for your child to develop increased independence from you, to shift the center of his social world from home to peers, and to explore and discover his talents and interests within a larger community of influence.
Teens this age also may become concerned with moral issues as they are able to grasp abstract concepts and are likely to recognize that breaking rules under certain conditions is not always wrong.
He can either have you take down the glass cup, or he can take down the plastic cup.
Sometimes disrespectful behaviour might be a sign that your child is feeling particularly stressed or worried.