Sounds Like a Teenager

The real basis of Buddhism is full knowledge of the truth of reality. If one knows this truth then no teaching is necessary. If one doesn't know, even if he listens to the teaching, he doesn't really hear.

-Ajahn Chah, "Taste of Freedom"

 

So when dealing with a teenager (though I KNOW its not just teens who think this way, that's just the chord that this strikes with me), how do you overcome this fact?
Even if she listens, she doesn't really hear?

How do you end up NOT sounding like Charlie Brown's teacher?