> I know a kid who is a lost cause, and his friends claim he took contaminated drugs; are they wrong?
Yes, they are wrong. There's no such thing as "contaminated" marijuana, that's an urban myth.
As far as productivity, it depends on how you look at it. You can be much more creative while using marijuana, it can also be great to boost productivity if you're tired or not in the mood to be creative...
It may have you re-examine if you want to overwork, make business your life, climb the corporate ladder... but all of those seem like positive revelations too and a much needed counterbalance to all of the pro-corporate propaganda we all drown in.