[AlexandrB]

I once had a very bad night and chain smoked 3-4 cigarettes. Since then I've never experienced the "light switch" you describe. The experience of smoking was not unpleasant, but not something I crave either. My sister seems to be the same way and smokes a few cigarettes once every few years when things are particularly stressful but never habitually.

I wonder if there are physiological differences that account for this difference of experience.

[mason55]

There does seem to be some kind of difference in people, which isn’t surprising. Things like alcoholism also seem to have a genetic component.

Anecdotally, my wife and I both quit smoking. Many years later she still has the desire every day whereas I go months without thinking about it (and if cigarettes weren’t common in society I’d probably never think about them again, let alone have a desire to smoke one)