I disagree with this, I have a teenager myself and he doesn't "know everything, it's pointless arguing with".That’s just being deliberately obnoxious. If you’re older, you’ve likely learned more. Unless you’re a teenager. They know everything, it’s pointless arguing with.
He is a very knowledgeable person and I often learn from him, and vice-versa, as we engage in many fascinating discussions.
I don't consider myself smarter since I'm older, I may have better knowledge in some subjects but he does too, I think it is honestly interesting to hear the opinions of the young people then disregarding them completely.