How do long-term smokers explain that their lungs are healthier?

A person who smokes for a long time can't explain that his lungs are healthy at all. Smoking is very harmful to his lungs. This is very bad for your health. Why do you have to prove smoking? Relatively healthy, then this person must be a heavy smoker and want to smoke. I think this is irresponsible to myself. Have you never thought about the people around you like this? If there is something wrong with your health, people around you will be very sad. So it's best to smoke less and try not to.