Realize that most successful ex-smokers quit for good only after several attempts. You may be one of those who can quit on your first try. But if you're not, don't give up. Addiction is constantly thinking about smoking when you're in a place where you can't smoke. Addiction is when the good feelings you associate with smoking outweigh the serious health risks you know are also associated with smoking.
Addiction is both a physical and psychological process.
The psychological need may surface whenever you smell smoke or sit in a certain chair. You may find yourself absent-mindedly reaching for a pack of cigarettes or a lighter as you watch television or talk to someone on the phone. Being stuck in traffic or sitting in a long, boring meeting may trigger the urge to light up.