Part of the reason for this might be that you are already suffering an addiction through passive smoking. There is no doubt that many would not be smoking if their parents had not. This point hardly needs elaboration. We need to go to the Word of God to inform our answer with His principles. It is evident that several factors are highlighted by the above facts.
Smoking damages the health of many people who are smokers, even causing premature death.
Even if you have a great-aunt who lived to a hundred and thirty while smoking 50 cigarettes a day and washing down hamburgers and chips each day with a bottle of whisky, you have no way of knowing that you will have her happy outcome. Smoking damages the health of other people - in particular the vulnerable babies and children. Smoking costs significant resources in hard currency. A smoker is an example for others to follow and hence a smoker leads others into a death-trap. Smoking is evidence of addiction and therefore a lack of self-control.