>>2
I'd say this would be valid in relation to smoking cigarettes (very little gain with huge damage). In relation to weed it isn't that simple in my opinion - there is a lot of upsides too. At least after taking all options into account (vaporizers, etc - i know those also work for tobacco but let's be real noone does this).
Personally i left the smoke-weed-regularly club almost 10 years ago but that doesn't mean i dislike weed or will reject offers when they happen. It's pretty good. Plain and simple. The weed induced tunnel vision is also perfect for writing code.