As an ex-smoker I never have the urge to smoke. The only thing I miss is the extra breaks at work which came with the territory - breaks that non-smokers are looked down upon for taking. No one seems to have a problem in most industries with repeated unscheduled smoke breaks, but if you're not smoking you'd better not be standing around doing nothing unless it's a scheduled break. This isn't true of all industry, only most that I have participated in (construction management/engineering/construction labor/retail management).
I started smoking again on the first day of my current position. Extra breaks, boss smokes - on some smoke breaks real business plans are hashed out, information is exchanged which normally wouldn't be, and a sense of comradere is shared which trumps the normal co-worker acquaintance paradigm - But now I have an e-cig and I only go out when I think it will be significant because I don't want to die.
At this point I miss the social aspects more than anything. It is nice to just step out with a few friends and chat for like 5 minutes.
I never experienced relaxation or pleasure from hurriedly sucking down a cigarette. I only experienced a nicotine high with the first cigarette of the morning, never with any subsequent unless I waited three hours for the next. A nice cigar on the other hand, that always resulted in relaxation, but that had more to do with the environment which came with the territory: a stick, an easy chair, some Blues emanating from my eighties-vintage Infinity speakers, and a pour of GlenDronach went a long way toward taking the edge off even the worst of days.
I don't miss that aspect as I'm a bit of a misanthrope on jobsites - smoking was something I'd do alone at work to give myself a break from having to deal with the ego battles that are part-and-parcel to building trade environments.