Not sure if troll or srs...
Smoking is pretty close to the worst thing you can do if you wish to lead a long and pleasant life (including the endgame).
Smoking has an unwanted effect on almost every cancer probability (including cervical/breast cancer for you women), every bronco-, cardio-, aortic-, pharyngeal- (all kinds), and endocrine- disease available (to name *but a few*). If this wasn't enough, the damage caused is from the smoke, meaning that second hand smoke is just as bad (and therefor affecting those in your vicinity to some degree as well). As a result, it's expensive as bloody hell to society, leading to a *deficit* in high-quality medical care socialist countries. Oh, and the nicotine itself, separate from ingestion method, also causes sleeping problems, gastro-intestinal problems, and headaches. So enjoy that.
For the poor epidemiologists around, smoking is a major pain in the ass, because it's a confounder in almost every damn longitudinal cohort study ever, meaning more math, more matching, more controlling for additional factors, and more tables.
On the plus side:
There are only two benefits that I know; the calming effect of nicotine can be helpful in reducing point stress (often negated by the *increase* in stress that comes from nicotine abstinence), and the *possibly* mild protection it offers from late-onset Alzheimer's disease. I say possibly because the evidence of this protection is no consistent.