Cancer of the mouth, tongue, and voicebox are common, and the treatment is not only incredibly disfiguring, but many patients lose the ability to speak. There are worse things than dying, I believe. Cigarette smoke greatly accelerates aging. Smokers have more wrinkles, and develop heart disease and hardening of the arteries much earlier than nonsmokers. This can lead to loss of limbs from gangrene, and kidney failure because of decreased blood flow.
Male impotence is another common consequence of hardening of the arteries.
Because they have a lower oxygen concentration in their blood, smokers are more prone to cataracts and lumbar disc degeneration. They have a propensity for poor wound healing, especially after surgery. Many smokers develop a chronic hacking cough, which can lead to emphysema and bronchitis. The worst cases become oxygen dependent, hooking them up to an oxygen tank for the rest of their impaired lives. Even young smokers have a decreased exercise tolerance, and perform worse than their nonsmoking counterparts on lung-function testing.