In my case, I enjoyed smoking. Cigarettes, pipe, cigars, usually all three in the same day. I quit in February, 1992. I was just shy of my 44th birthday. I held my father's hand while he died of lung cancer, actually drowning in his own body fluids. It was such a stupid, avoidable thing. He used to say if he had the guts behind his belt that he had over his belt he would quit. But he never did.
It was just senseless that he had to die. I loved him so much. I had to make his death mean something, at least to me. So I determined, then and there that if nothing else, I myself could quit. On his behalf. I knew, if he were still alive, that he would approve of that. So, in my grief-ridden mind, I could make his meaningless death mean something. So I did, I quit cold turkey.
For the next year, I don't believe I went 20 waking minutes without thinking about and wanting a smoke. The second year, I don't think I went a waking hour without wanting one. I mean, I was hard core addicted. But it's been 20 years now that I been off smoke, and the only time I miss it is if I happen to be around someone who just lit up. It still smells good to me. OTOH, when I walk into a place with stale smoke, it stinks!
YMMV, but this is my story.