I smoke, I enjoy the social aspect of it, and actually I just enjoy smoking anyway. Always have done, but I don't 'need' to smoke i.e. if I'm at home by myself I won't smoke, and can easily go for a week at a time without it even crossing my mind. I smoke much more at Uni though because there are always other smokers around.
It's not really a justifiable habit though. It has definite minor short term effects and possible long term catastrophic ones too. It's also **** expensive if you smoke a lot.
However, I do think that a lot of the time I get on better with smokers only because they tend to (in my experience) have a bit more of a carefree attitude towards life, which I find quite appealing.
Smoking will have to go when I start having responsibilities towards others and a less hedonistic lifestyle though certainly, along with a load of other stuff, but whilst I'm young I don't really give a shit.