It's like a long-time smoker saying that they have no reason to not smoke that next cigarette because it's not like that one cigarette is going to kill them.
It's not like that at all. Not smoking "that next cigarette," which we could define as not smoking any cigarette in the next 30 minutes, is a very important decision that has a very direct impact on whether they will quit long-term.
Well it probably won't, right? I too find this hard to reason about, whether regarding voting or cigarettes. Perhaps I'm just thick. Is there a concept in, say, game theory that deals with this?
I think an argument can be made that smoking another cigarette today will increase the odds of you smoking another cigarette tomorrow (And the day after, and so on) - which could a large effect on your health.
timeless decision theory: if you decide to smoke a cigarette in this situation it is likely that you will decide to smoke a cigarette in all similar situations.