My story:
I had my first smoke at a party in Grade 11. Not unusual, I imagine, but I never smoked again for another year and a half or so. One night I was up late in the early summer of 2004 (after I graduated) at my parents' house, and thought I smelled smoke so I went to check it out. Turns out my stepbrother was smoking in his room, he offered me one and I took it. I started with every so often - maybe once a month at a party. In the summer of 2005 I worked at a museum with a guy who owned his own car and smoked like a chimney in that car. Since the museum was in the middle of nowhere and the only way to get lunch was to drive 20 minutes to the next town, he drove me. He smoked a lot, and eventually I was, too. Three or four cigarettes a day at work and usually one at about 2 am at night, hanging out a window in my parents' house with a fan on full-blast and a full can of Febreze at the ready. My parents would have killed me if they knew.
But they never found out, and at the end of that summer I moved into residence. I went out two or three nights a week to the bars for the first couple of months and smoked while I drank, but I mostly gave up smoking during daylight hours once I moved out of the house. By the time December rolled around, I was back up to four or five cigarettes a day, in broad daylight. I had to stop cold-turkey when I went home for Christmas break though, and I got a (non-smoker) girlfriend, so I unintentionally cut back to only smoking when I went out to the bar - although I was smoking nearly an entire pack with my friends every single time I went out. Things stayed the same until May.
I then moved into the house I live in now with two friends from residence, both of whom would smoke about a pack a day between the both of them. I began smoking more and more again until the point where I was back up to about five cigarettes a day (sometimes more though). One day in June, I decided to quit. Just like that. I'd had enough of the taste (I never enjoyed smoking itself, only the head rush after). And somehow, I just stopped. I decided one day while smoking that it was my last, and it was. I had one smoke in August when I was drunk, smoked about two puffs but it tasted so awful that I put it out and resolved never again.
Fast forward to November 2006. I got a new job in a restaurant kitchen, and at least 80% of the people I work with smoked. The first day of work I wanted to go out and socialize with my new co-workers so I asked one of them for a smoke. And I didn't stop there, I smoked for a month, until mid-December. I've quit again. My last cigarette was smoked after I failed an exam on the 15th of December and I haven't had one or had the desire to have one ever since.
Here's hoping I don't start again.
But the point of that story was that despite being bombarded with stories of how bad smoking was and having lost more than a couple family members to smoking, I still did it anyways because of friends. I wanted to fit in. I think a lot of kids who start smoking nowadays have similar stories.
We know how bad it is, but we start because of some social reason, not because of celebrities who smoke. I consider myself lucky that I got out (at least so far) before I got to the point where I couldn't.