Drinking on the other hand DOES effect peoples mood, behaviour, confidence etc.
This is what always mystified me about smoking: at least other drugs have some effect, nicotine just gets you addicted.
Edit:
To be clear: smoking has no meaningful affect unless you're already addicted. A non smoker who tries their first cigarette is no more relaxed or confident or calm than they were before.
The same is not true for alcohol or marijuana or basically any other drug people use recreationally...