Clueless, but I'll give you a chance to defend yourself. You know this how, exactly?
I have read extensively on the subject.
Also, being a teenager when Woodstock occurred (I was to busy surfing at the time and was unaware of the "big" event). Also, I have seen enough others and the effects it has on them.
People who are into pot have real problems in their lives. I know that everyone has real problems, but the potheads are working through their problems at significantly lower level. Read some clinical literature, not that put out by a pot advocate or drug enforcer. Pot causes problems with short-term memory. People can not effectively deal with their problems in this state.
I do not believe that it is as destructive as some believe, and the penalties are too severe for possession. But it is bad news and should never be legalized. Logically possession of small amounts should be decriminalized, but the advocates would then be prone to declare total victory and twist the meaning of decriminalization beyond what it should be.