dear, smoking contains nicotine, which at produce transient feeling of high(euphoria) however, it does make one dependent on it as it highly rewarding. however, tolerance to this soon develop and it no more would produce same high rather a discontinuation of which will cause you distress and bad mood. eventually hamper your life. additionally the amount of carbon you inhale as a result of smoking will have a bigger toll on your arteries of heart. They will hardened and will get blocked soon. Predisposing to a cardiac and general condition called arteriosclerosis and therefore will increase chances of cardiac arrest 10 fold. thereforey advice give up smoking as soon as possible. thanks