It takes me 1-3 weeks to smoke a pack -- that's how I've been for two years now...
I've never tried to really quit -- but I'd say it would help to avoid smokers at all cost if you wanted to quit. That would mean never going to a bar w/ smokers or hanging out with your friends during your lunch break... ;( Also stop having sex -- j/k
Stop drinking beer. Because we all know a cigarette is so much better after a beer ;) heheh...
Seriously I think cardiovascular excercise is probably the best. See you were playing tennis and you wanted to quit. Try jogging... You will be coughing and coughing and hacking away the entire time -- that's good for you! You're cleaning our your lungs. Don't get discouraged that you are slow and you suck and little grandma's are running faster than you are... -- later in the day your lungs will hurt bad from coughing and you won't want to smoke a cigarette because you will feel the physical pain in your lungs from the smoke. Keep running and sooner or later you will want to improve your times and you'll realize that you could be a much better runner (and more healthy) if you quit smoking.
Anyway Go Fuck Yourself.
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...from the nectar of the Bone flows all that clicks...