Smoking is a hard habit to break because tobacco contains nicotine, which is highly addictive. There are several effects and causes of smoking; First of all, teenagers smoke because they want to be fit,. Teens see their friends smoke and they think it makes them look cool or independent plus them. Feel no tension plus worries. The first cause of smoking which is Nicotine is an addictive and harmful substance contained in cigarettes. It reduces tension and it is also believed that it can have a calming effect on people who are anxious and worried.