Also adding the caveat about the obvious downsides of smoking before I assert this opinion but one thing that's kinda gotten lost is those micro social encounters you'd get from sharing a cigarette. Whether at work, at uni, at a concert, in a bar, or just about anywhere, those smoke breaks used to be a chance to strike up a 5-10 min convo with someone random. Even today, head to a designated smoke area and more often than not, you'll end up chatting with some stranger asking for a lighter before going back to what you were doing. I don't think society has found some other mundane shared experience to replace this.