My parents both smoked. I've never had pneumonia or bronchitis. I smoked a little for a few years, until I got myself addicted in college. I had to work at it, though. The times I tried to quit later in life, I found it remarkably easy, but it was also remarkably easy to slip back into it. I quit over 13 years ago, and don't even miss it.

I do believe there are people who are genetically more prone to addiction than others. I think I just lucked out.