As the quote in my signature states, I just wanted a live better.
I quit at age 39 which I guess is younger than some of people here but I was suffering from a bad smokers cough, shortness of breath, low self esteem from being a smoker in a culture that was growing increasingly anti-smoking, trying to figure out how to get my next nicotine fix in this anti-smoking society, hating the monetary cost increase of cigarettes, deciding to finally quit smoking and then entering the horrible quit-relapse cycle, etc. etc.
Over time, I grew miserable as a smoker.
The freedom of a better life not fighting the constant struggle of the misery of smoking and all the BS that came with it is what led me to finally quit.