The fact that smoking kills is the stupidest reason to not do it anyway. Everyone dies and a lot of things can kill you. There are plenty better reasons not to do it:
It's disgusting. It has no benefit. It's expensive. It gives you gross diseases that will make you gross... like a green hairy tongue, coughing up globs of goop, etc. It smells bad. It makes you addicted and always have to worry about something. It makes you get out of shape. I could go on forever.
BUT MOST IMPORTANTLY: It makes you look like you dont give a shit about anyone you smoke around, because your directly poisoning them. YOUR FRIENDS, FAMILY, ETC.
I don't ever have strong opinions about anything, but I can strongly say that I have no respect for (cig) smokers. QUOTE ME ON THAT.