I think the main reason it helps people reduce stress is they have to leave a situation to go outside or to another room in order to smoke and they’re taking a deep breath. I found the feeling of breathing in the smoke (throat hit I believe it’s called) and then breathing it out and seeing the smoke cloud very satisfying. Similar to chewing gum I suppose. Also, I rolled my own filter-less cigs so I had the added element of rolling it and picking out strands of tobacco hanging out of the end whilst smoking as a kind of fidget action. I prefer vaping now and don’t think I’d go back to smoking cigarettes regularly but I have started smoking a cigar with a beer some weekends just in the last few months. As some have stated the actual feeling from the nicotine is similar to caffeine but more short lived.
Happened in the UK last year. I worked on an IT Service Desk where we had like 50 phones being rebuilt. I was in the building on my own on a weekend. I thought it was Armageddon.