As ex-smokers, we honor the acronym N.O.P.E. (Not One Puff Ever). But tobacco addiction is physical, mental, and emotional. Ex-smokers often breathe in family members' secondhand smoke, find their resistance and inhibitions lowered by alcohol, or associate smoking with so many areas of their lives that 'just a puff' can be hard to resist.
Brief smoking episodes are usually considered 'slips' by treatment specialists who recommend modifications in craving management to avoid escalation back into previous smoking patterns and levels, i.e., relapse.
It's easy for an ex-smoker who (under the influence of a few drinks on a Friday night) takes a few drags off a friend's cigarette, to decide, "Well, I've already smoked, might as well buy a pack/carton."
We want to prevent that. Research indicates that considering a break in abstinence an isolated event, focusing on lessons learned, and developing non-smoking reactions to stressors or triggers in the future, is more effective in helping the ex-smoker maintain their quit than is declaring the quit broken.