Smoking often begins without much thought; humans are curious by nature and want to try pretty much everything. Chances are that most people don't like smoking for the first time and wouldn't repeat it but if the people around them are smokers they will try twice and by the third time they're hooked. Then they either smoke pretty much for the rest of their lives without a second thought or they try on again, off gain to quit for years if not for the rest of their life.
Cigarettes are so dangerous because they help people in a lot of situations, they allow them to be calm and trigger conversations, make them feel like they're part of a group and so on. There are two addictive elements when it comes to cigarettes one is the cigarette itself which is addictive because of the nicotine in it and the other is the social setting. If everyone around you smokes, chances are that you will or are as smoker as well. That is simple natural, people want to be part of something bigger than them, they want to belong somewhere.
If you're trying to quit but are trapped by the two elements mentioned above there is a new thing on the market that you might like it's called Vapor Smoke. It's an electronic cigarette that looks almost exactly like the real thing only it's free of the dangerous toxins that traditional tobacco based cigarettes are full of. By using Vapor Smoke you can still continue to smoke and get the nicotine you need but without the dangerous smoke that damages your lungs.
Another great thing about Vapor Smoke is that it can be a huge step forward to quit smoking altogether if that's what you want. You can simply take less and less nicotine each week, since it's not damaging to your health you can take as long as you need to quit but just make sure that you take less nicotine each week and eventually you should quit smoking, of course a bit of willpower is required as well.