The only negative effects of smoking pot are the same effects of smoking any substance. It is not bad for your lungs.

Pot is actually very good for many other things. Rather than believing everyone tells you, try finding things out for yourself. I don't even smoke pot anymore but I know that if you're a somewhat responsible and intelligent person, there is absolutely nothing bad that pot can do to you.

I'd explain to you why the government makes it illegal if I had an hour and the motivation. But I know you wont be swayed, I've tried talking sense into people like you.

If you feel like opening your eyes to the FACTS, try reading this.

http://www.faqs.org/faqs/drugs/hemp-marijuana/

The guy explains everything there is to know, seriously, with sources. But like I said, I know you wont be swayed. I won't lose sleep over it. I know in the end I'm better than you just because I can form my own opinions.