I've been a 3+ pack a day smoker for 35+ years. Haven't had a smoke for 45 hours.
On my way to work at a Harley dealership in Reno years ago, everyday I'd see an older heavy set woman who rode her motorized cart to the bus stop. Strapped on the back was her oxygen tank , cigarette in mouth, mask on her forehead and I was always waiting for her to go kaboom!!