Neither does food, work, or relationships. Though marriage comes pretty close.
I've been thinking about this for a while now and I'm fairly convinced that we've been blaming the wrong things for most of what goes wrong with people's health. We look at someone who smokes two packs a day and say the cigarettes are killing them, but nobody picks up a cigarette because life is going well. We look at someone who's fifty pounds overweight and say the food is killing them, but nobody eats their fourth meal at midnight because they're at peace with themselves. The thing doing the damage is always underneath the thing we can see, and it's almost always some version of distress that nobody wants to talk about because it's easier to point at the cigarette or the cheeseburger.
I think work is the same. I've never met someone who burned out because the work was too hard. I've met plenty of people who burned out because they spent years reporting to someone who made them feel like an idiot (in a bad way), or because they sat in meetings where they couldn't say what they thought, or because they went home every evening carrying a weight that had nothing to do with their real job and had to do with the fact that they felt unseen and undervalued for eight hours straight. The work didn't break them but the way the work made them feel about themselves definitely did.
And relationships, honestly, are the worst offender. Nobody's marriage kills them (let's leave the abusers as exceptions that they are). But the slow drip of resentment from years of not saying what you mean, of going to bed next to someone you're performing for instead of talking to, that'll take years off your life faster than any cigarette will. At least the cigarette is honest about what it's doing to you. It puts it right there on the box.
I don't think this is a controversial take so much as an inconvenient one. Coping mechanisms are fine, and we all need them. For some time, even the bad ones like cigarettes, coffee, and alcohol can be fine, and I'm not against any of that. Not as stoic as some people might be. But I do think it's worth being honest about the stress that's causing you to reach for them in the first place, because that's the thing that needs your attention. The cigarette is just keeping you company while you avoid it.