Parents are the first role model to their children, most of the things children do they learnt it from their parents, so smoking in front of your kids is a bad habit because they will grow up with the belief that is a normal thing, and I know some kids will even start practicing from small like buying those stuff , hide in their bathroom and start smoking to see how it work and before you know it they become professional in it, and they start blaming society and think the system failed the children not knowing parents are big contributing factors to all this misconduct.
It’s crazy to admit that I had to quite a lot of habits and even cursing because of my growing child. My son will be 2 in a couple of days and he’s learning almost everything he comes across with, so I choose to be very careful with the things I expose him to, especially from us at home, I know there’ll come a time when he may go out and maybe learn a few things, but as long as I’ve not introduced that to him, I have every right to make him let go of such things and he’ll most likely listen to me, but if I’m actively involved in that thing and asking him not to do it would only make it even more difficult or impossible to let go of that thing.