Why do people smoke and use tobacco products?

when they know its bad for them and it makes them ugly. and it also kills four hundred thousand americans every year, it turns your skin yellow and wrinkled. And it makes you have upper respiratory problems and bronchitis, which can kill you, it makes you have cancer, and makes everybody around you not enjoy your presence when you smoke because it smells so bad. My mom works in a doctors office and one person was on oxygen and hes only like 45, and he said if i could change one thing i wish i would have never touched a cigarette, he said he never understands why he sees young people smoke because they know they're gonna end up like me. if u know its not gonna be easy to quit, why start