------------------------------------------------------------------------------------------------------------
i'm 30 and started smoking when i was 12. by the time i was 15 i was a full fledged pack a day smoker. over the years i have witnessed many people fall prey to the habit.
you start by smoking here and there, maybe you don't inhale at first, maybe you just like to blow it out your nose or smoke it like a cigar. it's only on certain occasions.
if you are fiddling with cigarettes, you likely have friends that are smoking, also. so you are hanging out, maybe having a few beers, and you see them smoking and decide to be social with them, and also have a cig, but alas, you have none. so you bum a few off a friend for the night. you kind of like it. it just feels good to have one with some drinks or just when you're talking and laughing. soon you do this every time you get together for a drink/movie/whatever. it's not a big deal, it's just once in a blue moon.
after a while, your friends start complaining that you are always asking for cigarettes but you never seem to have your own, you cheap son of a bitch. those shits are expensive. maybe next time you could come prepared and letother people bum them. so you buy a pack prior to the next gathering. it feels weird to order them at the counter, but whatever. it's only for the night and you feel like an asshole smoking everyone's cigarettes all night. you see how they act when they run low. you don't want to be that guy.
so now you have your own pack of cigarettes. it's just for the socialness of it. but at the end of the night you have leftovers. you leave them for a friend because what the hell do you need them for? the night is over. it's not like you're going to smoke them tomorrow.
eventually there comes a time where you decide you may as well keep the cigarettes you bought. they areexpensive and you're sick of having to buy them every time you go out, so you'll just save them for next time.
now, a weird thing happens when you have your own pack of cigarettes. maybe you'll get the idea to just smoke one after a shitty day, maybe you won't. maybe you'll have your own 6 pack while you watch the game. if you have a few beers, you will notice a strange urge to have one of those cigarettes. for the past few months, every time you've had drinks with friends you've had a few cigarettes. it's like they go together. it's just what you do. but there's no one else there, it's just you.
so you have a little debate with yourself. you don't need the cig, but you sure would like to have it. it's not going to ruin your night either way.
if you decide to have that cigarette, you have fucking failed. you are doomed. doomed. what you have done is solidified an association with having drinks and smoking cigarettes. it is no longer a social thing. you love the little buzz you get. you love playing with it as you sip your drink. you love trying to make smoke rings or whatever other cutesy shit you do to amuse yourself while you smoke it. you don't realize it, but you now have a habit. an itsy bitsy manageable habit, but a habit nonetheless.
you may now find yourself looking forward to outings with friends because you can't wait to have an occasion to smoke a cig or two. you might notice a feeling of "nakedness" if you have beer or two with dinner but no cigarette. you might hang out with your smoker friends on non drinking occasions and feel that same sense of something missing. then you see someone light a cig and it hits you. you want that fucking thing. shit. you have another internal debate with yourself about whether or not to have a cigarette without the drinks. you don't even have cigs on you. if you decide to bum one now, you are officially screwed. you gave in. now you've solidified an association between social occasions and smoking. you will come to expect this at gatherings. going out to dinner? let me join you for a cigarette. cookout? you don't mind if i have one of those, do you? i didn't bring any because i'm not drinking.
so now you smoke at social drinking occasions, you might smoke when drinking at home, and you also smoke when just hanging out. your friends again chastise you for bumming their cigarettes. buy your fucking own if you want one that bad, they say. you promise to bring your own next time...
now you smoke often enough to expect a cigarette after certain occasions. after dinner? smoke. movie's over? smoke. drinks at bob's? smoke. you dun goofed, and it's all downhill from here. you've accidentally built cigarettes into your life.
tl:dr a chain of events will lead to your expecting cigarettes on certain occasions, and if you buy them to fulfill this expectation, you're screwed.