Your child is working tempestuously toward one of the major goals of adolescence – leaning to be independent. In order to become less dependent, teens need to give new credence to their own ideas and opinions. They need additionally to believe that in separating from you they aren’t losing so much. Separating from the person who loves them most would be overwhelming and cause incredible grief, were that person not cut down to very human proportions.
It can help to understand this process and give teens the freedom to have and voice their own opinions without verbally abusing parents and family. As the teen grows in competence and independence, of course, he or she will feel more secure and able to agree with you on occasion and to admire and accept you in new ways.