My Dad's Dad died of lung cancer complicated by black lung, yes, he smoked, cigarettes, pipes, and did chewing tobacco in the end. I watched as a very wonderful man faded away to nothing. When he was diagnosed, he weighed over 300 lbs. within a year he was dead and weighed less than 100 lbs. I was not there to see his last moments, but I do not think I would have wanted to be either.
His wife also smoked. My grandmother would tell all my friends who smoked about the day she quit.
On her way to work one day, she stopped to buy a new carton, got back in her car, pulled out a fresh pack, opened it, and pulled out the first cig. As she was about to light up, she looked at it, asked herself why she was doing this, and could not find a good answer. She tossed the lighter, cigarette, and pack right out the window. When she got to work, she gave the remainder 0f the carton to a coworker who smoked, and she has not smoked one since. My grandmother was a stubborn women, and when she made a decision to do something, not even the good Lord could have stopped her. This was over 50 years ago, she has since passed, but not because of smoking; she beat that one.
I am 41, have never started, and don't plan to ever do so.
I should add, I do not condone those who choose to smoke that is their choice; however, I caution anyone who has yet to start, it just isn't worth it in the long run.