Motivation to quit is complicated. It’s not because you don’t understand how bad smoking is for you. And it’s not because you don’t care about your health. It’s because nicotine is a powerfully addictive drug that is capable of motivating us to keep using, more so than even alcohol or heroin. The fact that you can keep smoking despite your experience is not a function of how weak you are, it’s a function of how powerful nicotine is.