In terms of what is responsible, I'd say it depends whom you're considering. If a father enjoys a glass of wine every night, it might be arguable that it this behavior is bad for his health in the long run, through a minuscule increase in his chance of digestive cancers. If he enjoys a bottle of wine every night, on the other hand, there is a serious problem, mainly in that he's practicing potentially risky behavior that could put his children at risk (mainly of neglect). There's no doubt that a bottle of wine a night isn't good for the father either. So where's the line?
It really depends on his analysis and the marginal utility he gains from the experience and his own approval of his behavior--something we cannot know completely. For me, I use the drug of caffeine every day, in the form of 1-3 cups of coffee. When I drink coffee at night (usually 2-4 more cups), I get tired around the same time the next day. I consider this abuse, and try to avoid it when my self-control allows me. Similarly, I consider the smoking of any cigarettes abuse, because I am a singer and it's bad for my voice. However, I still occasionally smoke 1-5 at parties.
Marijuana? For me, this is more of a situational activity (like a wild party with alcohol). I usually smoke a few bowls, depending on the number of people and quality of weed. I consider this acceptable on a perhaps biweekly, social basis. However, when I was a junior in high school, I smoked weed 2-4 times a day (on weekdays): Once in the morning with one friend, once at lunch with friends, one after school with the same friend as in the morning who gave me a ride home, and sometimes in my bathroom at night. Obviously that was unhealthy.
I've done salvia many times, but since the nature of the drug is that you "break through" only once and then lose the desire to do so, I am still unsatisfied, since I've never smoked enough in a sitting to "break through". I've tried cocaine and LSD only once each. I would consider it unacceptable to snort cocaine again, simply because I liked it very very very very very much (it's like coffee, which I tend to get addicted to, but better), and therefore I'm wary of becoming a habitual user. LSD didn't really do much for me, so I'd try it again to discover its effects.
Sorry that was a bit of the tangent, but it might be useful for those of you that haven't used these sorts of drugs to understand more about them, and what one user considers acceptable behavior.