I saw some research on this. Depending on the survey, between 90% and 100% of all ex-smokers who relapse ("just one") end up smoking at their full former rate. In other words, once you have stopped smoking and have a choice, the choice is very clear:
a) Never smoke another puff of a cigarette
b) Smoke all the cigarettes again (7500 a year for a pack a day smoker)
There's no third option. So, if you are trying to quit and visualizing that one cigarette, think again. What you should be visualizing is a bucket with seven thousand five hundred cigarette butts (for just the first year). Is that what you want? Or would it be better to just take a few deep breaths until the crave passes?