Yeah, smoking and alcoholism sort of run in the family, so I've seen my fair share of it's negative aspects. All of my grandparents except one smoked, along with most of their parents, as well as my uncle and one of my aunts, yada yada. I won't go into the drinking.
I suppose what it comes down to is poor coping mechanisms. I've never really handled stress, sadness or other negative emotions well and I often feel way too overwhelmed by work and life to seek out or participate in more healthy activities. If I only have five minutes of free time, smoking a cigarette is just enough to make me feel like I got
something for myself in. Otherwise my mood starts to steadily decline which spirals into other poor coping mechanisms. Ironically enough, participating in this forum and goofing off with L4D and Dwarf Fortress or watching cheesy horror movies are some of my other coping mechanisms due to how they're rather cheap and easy to fit into my schedule. Yet for whatever reason, the people I know give me more shit for liking those things than they do for my other habits.
Why are you wasting your time watching tv, playing video games and goofing off on the computer instead of doing something productive or going out? Well sorry but I've been working all day, feel completely drained and I don't have enough money to do anything else on my free time, even assuming I wasn't too damn exhausted to do anything anyway. Oh that's the other thing. I'm not sure why but I'm really tired all the time, probably from sleep deprivation, and even when I try and catch up on the weekends, I still feel like crap. Also frequent migraines are totally a thing for me, even before I started smoking and had to deal with nicotine withdraw.