If you give up smoking:-
You can stop panicking that every tiny twinge is the onset of a deadly illness, Lung Cancer, brought on yourselves.
You will be able to breathe more deeply.
You will smell nicer.
You will no longer smoke silly or sick on a big night out. You think you like to smoke when you are drinking, but the reality is you chain smoke till you are dizzy and then get a worse hangover.
You will stop the damage to your voice.
You will have better skin and be fitter.
You will save money.
You will have better chance of having healthy kids.
You will have more time to think about other things, not always be planning when you can smoke.
You will improve your relationships with your non-smoking family, who you always walk out on after a couple of hours because you are so desperate for a cigarette.