why do people smoke?

I know many people who smoke and I have asked almost all of them this question and I get the same answer almost every time. They say it makes them feel better and that it relieves stress. In truth it does not relieve stress and will actually increase it over your life time.

I don't smoke myself, but my cousin smokes. She stared when she was 12 and then didn't really have a clue about it being dangerous because both my uncle and my aunts smoked. My uncle still smokes, my aunt doesn't anymore. My cousin wants to stop in a way I think, but it is hard to quite a habit you've had for more than 20 years.