I believe it's human nature for us in your youth to want to establish independence early on and have our views acknowledged and respected. Being a child is a very "powerless" position to be in.
We hated having to ask for permission or being told "no".
From a child's point of view adulthood represents freedom!
One of the reasons many teenagers don't confide in their parents or seek their guidance in making decisions is because it proves (they) are not adults. They'd rather consult with their peers who view them as being equals. Teens want privacy away from their parents.
Parents and teens tend to live in "parallel universes" that only intersect when there are problems. This is even more so now with every bedroom having it's own TV and laptop as well as each child having their own cell phone. Some teens go straight to their room after school and don't leave until the next morning.
Parents become nothing more than Human ATM machines.
Lastly there is the "generation gap".
Every child/teen feels like what (their parents) learned or experienced is "outdated" or doesn't apply in "modern times".
If it weren't for the teen's own existence he/she wouldn't even believe their parents ever had sex!
However they still refuse to believe parents know what it's like to be "in love". Teens also believe they're going to "have it all" as adults