People used to smoke in public: everywhere, and all the time. They smoked for fun, to relieve stress, out of peer pressure, to lose weight, to rebel, and because they were addicted. They couldn't stop.
With recent studies, we as a society now know the consequences of smoking. Reading off of a pack of Marlboros: "Surgeon General's Warning: Smoking Causes Lung Cancer, Heart Disease, Emphysema, And May Complicate Pregnancy."
These are the serious, medical reasons not to smoke and they are literally ON THE PACKAGE. Not to mention all of the other side effects that can harm you socially: constant coughing, yellow teeth, grey skin, and smelling absolutely disgusting. The kicker is that people are well aware of this, they have the knowledge, they've seen others fall victim, but they still choose to smoke.
A choice is a choice, and everyone is entitled to his or her own. If you choose not to smoke, you should have a right to clean air.
Many states have laws enacted that prohibit smoking within twenty feet of restaurants and public areas. They also have designated areas where those who choose to smoke, can without bothering those who don't. This is a practical and fair step in the right direction, but not all states have adopted it.
Even though some states and some places follow this no-smoking concept, there are many that still don't. As someone who doesn't smoke, there is nothing worse than going to a restaurant and having to breathe in secondhand smoke or coming home smelling like it.
I'm not saying secondhand smoke will kill everyone. Someone can smoke his or her whole life without any problems, and someone can never smoke and get lung cancer. There are no guarantees, but when it comes down to it, clean air is courteous to all.