ANDY'S ANSWER: Teenagers have a smart mouth only if they have been allowed to get away with that kind of behaviour and don't have enough maturity of their own to figure out the difference between being smart and just smart-mouthed. Popular TV programs appear to have had an influence not only to teens who now see rudeness as entertaining and funny, but also as normal to their parents and teachers who SHOULD be correcting their bad behaviour.
Disrespecting women and others is also a learned behaviour. If it appears to be acceptable conduct and a shared attitude from the people around him, he will feel very comfortable in treating people badly. Unfortunately for him, once he is an adult in the real world, he will discover that his ignorant behaviour will not be tolerated in most successful circles.
Below is the recording of Andy answering this question.