I've been told smoking sharpens your mind, relaxes you, calms you, keeps you from yelling at the kids (or spouse), tastes good with coffee, tastes better after a meal. In short, makes you feel "better". (I always ask "better than what"?)
I know you don't really believe these reasons, or why would you be trying to stop smoking. Still, a part of you DOES believe these reasons.
The obvious and overlooked part is you must have a strong reason to continue smoking or you would have already stopped. By the way, there is no law that says your reason to keep smoking has to make any logical sense. It rarely does.
Almost all of the reasons you continue smoking can easily be proven wrong. Example: Maybe smoking helps you relax during work breaks because you get away and go outside to do it.
And most of the time you're AWARE it doesn't make sense. That doesn't change anything though, does it? Just one more log to toss on the fire of your motivation to quit. A fire that doesn't have much chance against the ocean of your craving to smoke.
It's basically about two things. The motivation that smoking will make you feel better and the feeling that you're trying to feel better than. That is all.
If you're hungry you feel like eating. If you're tired, you feel like sleeping. If you feel bad (stressed, over-burdened, upset, alone, whatever...) you want to feel good. And, whatever your mind has learned feels good, you feel like doing.
This is simple explanation of a craving. Some smokers have more than one type of craving, the 'first thing in the morning' craving might feel different than the 'on the phone' craving.
SO, how do you change these things? I can write on and on about this (and I have on my web site) It will come down to changing the feelings, motivations and beliefs involved.
First, the bad feeling needs to be helped. If it's about stress, get it managed, if it's a difficult situation, do what you can to take care of it or get some help. If it's a bad feeling you get that is beyond what the situation deserves, behavior modification might be what you need.
Second, the belief that smoking makes you feel good (it is often the mistaken, and understandable, belief that smoking equals being an adult, in control, strong, capable, etc...) The fact is, smoking is some plant leaf and chemicals wrapped in paper. The good feeling you're looking for, and sometimes experience, is created by YOU. YOU make yourself feel better when you smoke. You can make yourself feel just as good when drinking a glass of water. If, your mind believes it.
And that's the bottom line. The bulk of the quit smoking issue is about behavior modification - changing the way you feel. That's why the success rate of most prescription medication and nicotine replacement (like the patch and nicotine gum) alone is so low. The only current exception is Chantix and even Pfizer, the makers of Chantix, recommend behavior modification go along with the medication.