Well, you certainly have your opinion....However I've known lots of people that did coke on an occasional basis, quit and would never think of doing it again. Some people can do heroin occasionally, though I wouldn't try that, either! Meth...that's a tricky one. I do think most people should NEVER give that poison a go...quite addicting, even after one time.
I had friends, a young married couple, that smoked 4 cigs each a week for years. 2 each Fri & Sat with 2 adult beverages. I thought they were very cool. Cigs are VERY hard to do occasionally.