No, I've never been visited by the fine folks who work for Alcohol, Tobacco, and Firearms. However, I have experiences with each of these things.
Alcohol: Well, let's just say this problem plagued both sides of my family, i.e. there were people on both sides of the family with issues. I don't recall my mother ever having a problem with it while I was a kid, but it certainly became a problem later. It's probably still a problem now. My dad, well, I recall a few incidences with it. My memory of that time isn't so great, so I don't know the extent of the problems. He recently told me he's been sober for several years now, which is a good thing.
In any case, seeing the problems that alcohol caused in my family, I took a very cautious approach to drinking. I didn't do a whole lot of it until I was 21. I had a couple of instances in college where I definitely had more than my share. Jack and Coke. Lots of Jack, not so much Coke. Got that out of my system. These days, I will drink at a party or if I'm traveling (i.e. when someone else is paying), but I rarely drink at home, if ever.
I recently brought home a six pack of beer from the store. This is a rare thing, and it made the wife a bit nervous given my family history. She admitted to be she is being overly cautious about it, though I can certainly understand. The beer I bought is still sitting in the fridge in the garage. I did drink one of the beers. It sucked.
Tobacco: My father and my granny smoked often while growing up, so I grew up around smokers. My first "experience" smoking a cigarette was, when I was 7, granny asked me to hold her cigarette while she went to the bathroom. She was in a wheelchair, so needed both hands to navigate into and out of the bathroom. Being the curious lad I was, I put my lips to the cigarette to see what the big deal was. She caught me and told me that if she ever caught me doing that again, I'd have to smoke a whole cigarette. Considering how disgusted I was at that mini-drag I took, I decided right then and there I didn't want to smoke again.
Well, that didn't happen. Later in life, after college, I did smoke. I'd call it "socially" smoking because I would only do it with other smokers and the most number of cigarettes I've ever smoked in a day is 2. Any more than that made me ill. Once in a blue moon, I will have a smoke with someone. But I feel so disgusting afterwords. The smell that permeates everything on me. The taste in my mouth.
Speaking of the smell, every time I would come back from my dads, I would have to fumigate myself and my possessions. Everything stunk to hell and back of cigarette smoke. I was recently reminded of how badly that could smell when a co-worker of mine got a backpack from work to give to me. He is a definite smoker and the bag reeked of it.
There was a time when I was a kid when I begged my dad to stop smoking. I used all the usual arguments people use, at least as well I could make them at about 12, but the main reason I remember is that it was just disgusting. I eventually gave up asking him to do so when I realized that there was nothing I could say to make him quit. I'm sure he's still doing it to this day and, unless he decides otherwise, he won't quit until he dies.
Firearms: My one experience with firearms was with a bee-bee gun that some adult associated with my mom let me fire. We went to some place around Boulder Creek (where we lived at the time) and found a place in the woods where we set up some cans. I got to do some target practice. Other than fake firearms (e.g. video games), I've had no experience with real firearms.
I believe people should have the right to bear firearms. It is, after all, in the Second Amendment. If people want to have guns in accordance with the various laws, I'm cool with that. In fact, I tend to agree with Robert Heinlein who is often quoted as saying "An armed society is a polite society." Banning guns will only keep guns out of the good guys hands. All this being said, it is unlikely that I will be purchasing or carrying a gun anytime soon.