The reason people start to smoke are the same reasons people start to drink coffee, or tea, or beer. Nobody likes any of those things when they first try them, but they choose to acquire the taste, for either social reasons and/or because they want the side effect (caffeine or alcohol). In the case of cigarettes, the social effect has been very strong but is declining, and the wanted side effect is illusory, but as long as people still think that they will get something from nicotine, people will start to smoke, or vape, or chew, or snuff, or whatever form it will take in the future.