Some of you guys are mixing marijuana in with all the other stuff, and it simply doesn't compare.
I am a user (big surprise), and I can honestly say it does not affect my life in any negative way (except for the spending money part). I'm a responsible professional (manage an IT support desk for a fairly large construction management company), and would never even think about going to work stoned. I'm actually highly respected by my peers, and I imagine if they knew I was a stoner some would probably lose respect just for that (which is based on ignorance IMO).
Aside from traffic accidents, there is not one documented death due to marijuana. Almost all negative results from usage or possesion are based on outdated laws (meant to stem Mexican immigration of all things). America believed the lies that were spread about it so many years ago (reefer madness - lol!), and that's what we're stuck with unfortunately.
I actually stopped for almost a year recently just to see if my life would be better without it.
Guess what? No difference in my life at all (except a little less money again - lol).