I've got one of those stories. I abruptly stopped smoking when I shipped out for Boot Camp. I also suddenly lost a massive amount of caffeine- coffee wasn't something you got in Boot. I was smoking since about 14 years old, not a whole lot (maybe a pack or two per week- I had older friends that could buy them for me). I was certainly addicted, and I would get cravings and such. I smoked a lot more leading up to my ship out date, to help me deal with the nerves. Then, I shipped out. I was on my own, with a group of other recruits at an airport where I smoked my last cigarette, then some Marines that were there waiting for us made us empty our pockets and throw a lot of shit out before we got onto the bus that took us the Parris Island. At first, I didn't really notice it. I didn't crave nicotine the way I did outside of Boot Camp- I think it's because I was so focused, so overloaded with other shit, just trying to get through every day, every task, that I didn't really notice the withdrawals. However, after about 4 weeks of training, I suddenly felt really cold. It was like, late July in South Carolina, one of the hottest years on record at the time. I approached one of my Drill Instructors, and said "This recruit wants to roll down his sleeves, because he feels cold, sir." He took one look at me, put his hand on my forehead, and immediately replied "You're going to medical". At medical, I was seen by a Navy nurse. She took my temperature, and said "Bet you feel like shit." I was like "I guess? I'm just cold". Turns out I had a pretty high fever, and then they listened to my lungs. Sent me for a chest X-ray. Turned out I had a bit of fluid in one of my lungs, AKA pneumonia. They gave me a powerful antibiotic and put me on bed rest for 5 days. During that time, I coughed up some of the weirdest shit I've ever seen. Chunks of what looked like dead lung tissue and all kinds of other gunk. It was like my lungs were trying to clear themselves out, once they "realized" that there was no more smoke coming in. I recovered after the bed rest, and continued into Boot Camp. I only thought about cigarettes whenever we went somewhere and an Instructor or a Marine had been smoking there recently- that smell would trigger an intense craving. Other recruits said the same, they'd kill a man for a smoke, etc.. After we completed the Crucible, a final series of tests, you are officially deemd a Marine... and you're allowed to hit up the little convenience store. Guys bought candy, sugary drinks, chew, and of course cigarettes. I remember smoking that first cigarette after about 13 weeks- it was like the very first time I'd ever had one, felt strange in my lungs and made me dizzy as shit. It was also amusing seeing all of the new Marines lit up on sugar highs- a bag of Skittles was like meth to a man who's only sugar content came from the occasional Powerade. Was that story interesting? I've heard of people getting respiratory infections when quitting smoking, I always assumed it was the body's way of clearing out the lungs or something.