It certainly is a tricky habit to understand, especially if you've got it.
I quit back in 1978 at age 26 after smoking since 17. I was major league hooked. Quit a thousand times. A real love/hate relationship with cigarettes.
Then I flipped a switch and quit. It was tough for a year when I had a beer. Then for about 10 years I'd buy a couple or three packs a year. Smoke each pack in a day, usually when out with a buddy drinking. Those years were when I truly enjoyed it without feeling the addictive aspect, just pleasure. Then eventually I just lost interest in even doing that.
I consider myself fortunate not to have that lingering desire, as many former smokers tell me they have.
I know that there are triggers. For a lot, it may be a beer or a glass of wine. For others, it is talking on the phone or even driving in the car. I wonder if some of the better/more successful treatment programs don’t actually advise you to stop doing a triggering activity for a period of time (if possible) until a person feels a bit stronger along (without the nicotine?)