"The nicotine in inhaled tobacco smoke moves from the lungs into the bloodstream and up to a smoker's brain within seven to 10 seconds. Once there, nicotine triggers a number of chemical reactions that create temporary feelings of pleasure for the smoker, but these sensations are short-lived, subsiding within minutes." Nicotine's Effects on the Brain
ALWAYS keep in mind that the hit of dopamine in your brain when you ingest nicotine only lasts until it doesn't, and your brain starts to demand its next fix, and its next, ad infinitum. This addiction does not let go until you decide to end your dependence on it. You CAN get your dopamine in other ways - some chocolate, listening or dancing to music, any kind of exercise - even marching in place. You need to make that decision, though, and nobody can make it for you.
Do it and MEAN it - all else is just clutter!