I was never a heavy smoker, at most a pack every 2-3 days, and I quit for good probably 25 years ago. The more I worked out (I was big into karate) or rode, the less appetite I had for smoking. Smoking became inconvenient and expensive- couldn't do it in the house or workplace anymore, and I switched to a cheap menthol brand- then I didn't even enjoy the taste anymore!

My first wife had cancer,seeing what she went through- and other patients, well, it's rough. I lost a good friend, a smoker & drinker, to a stroke at 54, his bar buddy, too- except he didn't die, he ended up in a nursing home. And my uncle who smoked Camels spent his last years carrying around oxygen until he died from emphysema.
The part of us that is addicted doesn't want to see or understand these consequences, it's up to our conscious selves to overrule that voice.