Not quite. For some things, damage caused is simply a linear function of quantity. For other tings, it's the probability of damage that is such a function. Just in your example, a single journey in a car can kill you, but it's less likely than being killed when you srt out to make a thousand successive journeys.

As for adddiction, that's not about over-indulgence but compulsive indulgence. As for smoking, the issue isn't necessarily death -- say your clothes stinking and your tongue desensitized to tastes for two hours after a five-minute exposure to some smoke-filled room is bad enough.

_{*Lunatic*, n.
One whose delusions are out of fashion.}