We don't smoke because of boredom, telephone calls, computers, work, drinking, bathrooms, newspapers, driving, friends, romance, depression, or because we just walked out of a store. We smoke because we need to raise our constantly falling blood nicotine level and keep it in the comfort range so that we don't feel the craves of early withdrawal. Let me give you just two quick examples. First, you probably believe that smoking reduces stress while in truth smoking has never reduced one drop of stress in the history of the world. When a non-smoker gets a flat tire they don't reach for nicotine, they reach for a jack.
Smokers make every flat tire type situation in life far more stressful than it needed to be.
One more quick example among the hundreds you need to learn. The most common cause of concentration difficulty when quitting is due to low blood sugar caused by the fact that nicotine had assumed some control over regulating glucose levels and your mind has yet to adjust to resuming full control of production. Cancer has a beginning and so does disease. Don't believe what they tell you about quitting. There is no pot of gold at the end of the quit rainbow - it's better than gold.