I picked up smoking in my late teens and early twenties. I tended to smoke socially, but still sometimes smoked by myself. Probably about 2 years into I thought "this is dumb", and just stopped. I never felt addicted. Quitting wasn't difficult for me at all - at the time I was pretty busy so I didn't even really miss it. Basically, I just really don't have an addictive personality or whatever other part of our genes causes people to get addicted. I could quit without a second thought, but many other people I know who started around the same time I did are either still smoking or have had a hell of a time trying to quit.
I bring this up because there are so many things that we think of are due to an excess or lack of will power (this view is especially prevalent in the US) - if you are overweight it's because you lack willpower, if you can't quit smoking you lack willpower, etc. etc. My point is that this is usually not true. I was able to quit smoking not because I had a ton of willpower, but because I didn't need it.