One of the things I see spoken about repeatedly on stop smoking forums is "craves", although I have never seen a good definition of what constitutes a crave.
Quitters crave cigarettes, as though it it's maternal instinct to suckle their mothers breast in order to survive; Cokeheads snort cocaine until the next snort of cocaine becomes available... making it happen if it doesn't come naturally, seeking elsewhere if they can't get their fix...
It seems that for some people, the crave is like a dream; something they aspire to in a detached kind of way. If it isn't there, then they simply can't have it. Others seem connected to cigarettes in a fundamental manner, like they would go out of their way to realize the event.
Craving happens inside our heads.
For some of us, craves stay in the head. For others, craves drive us into action.