(Repetition>>that's what I tend to do here)
In it's simplest terms repetition, is doing the same thing many many many times.
When you add a chemical (pleasure release) to repetition, your brain retains connections to the emotions experienced during those periods of pleasure.
Our most basic animal nature seeks pleasure. Who wants to feel bad when you can feel good?
Societal conditioning attempts to attain a social norm (the "I don't want to feel like a weirdo" conformity?) which helps prevent violence and helps us feel like we belong to something which validates ourselves. Who we are is the sum parts of our experiences and resulting beliefs.
Not too long ago smoking was accepted as a social norm, remember?
Between using nicotine and making it part of our routine, the mental connections to the emotions experienced while we were having a cigarette is what we will learn to leave behind when we quit smoking.
It takes considerable time to disconnect from all the old connections, but, It doesn't have to be a fight if you understand what is going on "in the background." This is why simple phrases like "I don't do that anymore" bring you in the present and refocus you.
Unlearning smoking by making new memories without smoking and letting those memories replace the old ones will disconnect you from smoking FOREVER.
Time Is The Healer. The Only Way Out Is Through.