Why are you so anal about something so friggin' trivial? Using 'mad' as an adverb is not a big deal. It's called dialect. Its dynamics are what engage culture to change. The romance languages, and therefore, English were derived from these dialects.
In short, using language in the wrong way is a good thing. So stop thinking you're proper and mature by thinking that teenagers that say mad as an adverb are stupid. They're not. You are.