Pointless
Drugs and cigarrettes are stupid. Maybe you already agree, maybe you use one of these products right now, but I will never in my life try a cigarette or take drugs for any reason.
When it comes up in conversation, I go silent. When I see someone smoking nearby, I subtly cover my nose. When someone cracks a joke about crack, I fake laugh because I know I can't convince them anything different from what society has taught them. I don't even try, because I know what their arguments will be, and that addiction hears no reason. The only thing I say--the thing I find myself saying more and more nowadays because a conversation can't stay away from these topics for long--is this:
"I have never smoked or done drugs in my life, and I never will. Period."
Guess this isn't really the right prompt because I'm not trying to convince you to agree with me. I just know that if you disagree then there's no real way to convince you otherwise.