system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: With all the cancer research, public education and millions of deaths, why do so many people still pick up smoking cigarettes as a ling term habit?

I will say, I did smoke for almost 6 years, from 16 to 22, and have not touched one since (I'm in my 30's now). My reasoning then was "why not, I can always quit", mostly because I had no role models or adult figures in my life really paying any attention, and I was a bit self destructive... even then, I knew it was bad and it took a good 5-6 years for my lungs to really feel like they were healing and for my lung capacity to feel normal again. Is it because education still does not reach certain demographics? do people just ignore it? I am not referring to someone older who has maybe been smoking and addicted for years already, but mostly I mean younger folks who are just now being presented with life's various vices. What would make something like this appealing  in 2016 with all the negativity that surrounds it?

*EDIT: Typo in title, I meant "long term habit"
*EDIT: Thank you all, there some very genuine responses in here. I would like to say, I wasn't juding anyone for the act of smoking, as I said, I smoked for several years basically because I had nothing better to do and no one caring enough about me to pay attention. It just seems like in the past decade there has been a huge surge in public outreach and anti-smoking campaigns, more so than I ever remember when I was a kid... geez, just about everyone I know even in middle school was smoking outside the shoproom hallway door lol. It seems like you hear more about it in recent years and about the drastic effect its had on social circles now that its no longer looked at as "cool" as it was in previous decades, but from everyone's responses, it seems the same old reasons are well and alive, and the human spirit lives on. Thanks for the awesome answers!
gpt
Because no one really picks it up with the intention of becoming a long term habit. cigarettes aren't just a habit, they're a delivery system for a drug. As with most highly addictive drugs, it starts with "just this one", then you have another the next weekend, then you have a stressful day at work and decide you could use a little something to unwind, then it's every weekend and sometimes on weekdays. After a while, your tolerance builds up and next thing you know you're smoking every day. 

Its the same cycle every time. You know it's bad from the get go, but your infrequency of use means you don't really worry about the negative effects of addiction. It eventually turns into an addiction, and then they health effects take a back seat to feeding your addiction.

Source: former pack-a-day smoker, heroin addict, overly frequent coke user, and physician enabled amphetamine addict.