I've never smoked in my life, and i never intend to. I know a lot of people will say give it a shot and such, but to be honest, i hate the stench it gives off. My mum and step-dad are both smokers, mum more-so than my step dad, and it does bother me, however i won't tell them to stop doing so just cause i hate it. The main problems i usually have with it was the smell of it, and usually me ending up smelling of smoke as well, and i know i had a couple people tell me of it too.
Asides from that, i've never figured out the whole reasoning as to why kids do it, bar the idea of it making you look "cool". It just seemed stupid to me, but there we go.