I'm a daily smoker who smokes anywhere from an eighth to a quarter a week. I've been smoking for about two years, and I haven't experienced any serious negative effects from my habit except for those caused by the fact that the government is utterly convinced that this substance is so harmful that not a single citizen should have the choice whether or not to ingest it, unlike tobacco or Drano, and that it is so destructive to society that like enriched uranium nobody can possibly be trusted with it except for government officials (who as we all know are perfectly clean, moral and uncorrupt people).

But I digress. Cannabis has not significantly affected my memory to the point where it causes major problems. Occasionally I'll forget what I was just thinking about but that doesn't really matter as I don't do anything terribly important when I'm that baked. Usually I'll just be playing a game, surfing the Internet, watching TV or something.

My lungs haven't suffered either. Occasionally I'll hack up blackish-brown loogies but I'll just look on the bright side and be happy to have coughed up that crap. I can run and do other physical activities as well as I could before I started smoking.

In all of recorded history there has not been a single documented case of someone dying directly from cannabis use, so I don't worry too much about long-term health effects which I expect to be pretty minor. But even if it did give me cancer somehow, to quote the employees of the tobacco company from South Park during their singing and dancing number:

It makes me feel calmer when the day is at an end,
And if it gives me cancer when I'm eighty I don't care,
Who the hell wants to be ninety anyway?