You know smoking is bad for you. This has been a well known issue for decades. 
There are no more dangerous toxins in tobacco products, from acetone and tar to nicotine and carbon monoxide. The substances you inhale affect more than just your lungs. They can affect your entire body.
Smokers are three times more likely to die than never smokers. 

Here are common myths about smoking:
 

Myth 1: An occasional smoker doesn't hurt 

People who smoke only a few days a week or only at certain social gatherings sometimes think they can avoid risk. Nonsense! We know that every cigarette you smoke harms you. There is no safe level of exposure to tobacco smoke. Even relatively small amounts damage blood vessels and increase the likelihood of blood clotting. This damage causes heart attacks, strokes, and even sudden death. We know that smoking just one to four cigarettes a day doubles your risk of dying from heart disease. 
 

 MIT 2 : "Light" cigarettes are safer.

Cigarettes made of various filters, papers or tobacco blends used to be labeled as light, ultralight or mild. So some people bought them thinking they were better for you. Research shows that light cigarettes are not healthier, and in many ways these products have been manufactured and marketed in a way that is misleading.

MYTH 3: Too late for me to stop. 

Even if you've smoked all your life, it's worth stopping.

"If you quit smoking at any age, you will improve your health and quality of life," says Dr. Dorothy Hatsukami, director of tobacco research programs at the University of Minnesota. Your heart rate and blood pressure will drop immediately, and your lungs will start working better. Quitting smoking gives your body a chance to heal the damage caused by smoking. These benefits will be realized almost immediately after you quit smoking.

After a year, the risk of developing heart disease is halved compared to that of a smoker. After 5-15 years, your chance of having a stroke will be equal to that of a non-smoker.

MYTH 4: E-cigarettes are a healthy choice
A US surgeon said e-cigarette aerosol could contain harmful chemicals including nicotine, ultra-fine particles that can be inhaled into the lungs, aromas associated with lung disease and heavy metals. There is no safe way to smoke. Replacing a cigarette with a cigar, pipe or water pipe will not help you avoid health risks. Cigarettes contain around 600 ingredients, many of which are also found in cigars and water pipes. According to the American Lung Association, when these ingredients burn, they generate over 7,000 chemicals. Many of these chemicals are poisonous, and at least 69 of them are linked to cancer.

MYTH 5: Smoking isn't so bad if it's my only vice.

Even if you exercise, eat fruits and vegetables, or otherwise take care of yourself, you still can't smoke. It boils down to the fact that every cigarette you smoke is doing you harm. It is the leading cause of preventable disease and death. The best way to reduce the risk of smoking is to quit smoking altogether, not to exercise more and eat better.