My great granny chewed tobacco until she was 97.... no, really, factual statement: she did.
Cancer rates from tobacco are quite high, compared to death rates from childhood diseases, and COPD and all the other unpleasantness that comes from smoking are plain for all to see.
Chicken pox seems to be becoming a problem child for the developed world, again. Even with exposure and/or vaccination, adult recurrence is causing all kinds of nasty problems for people, including my mother's brother and my wife's mother. For me, the jury is still out whether or not vaccination, or childhood exposure offers better protection later in life. I think both of my older family members with varicella problems today were "lucky" and missed childhood exposure.