Smoking in public
Quickly light a sigaret? Think twice where you'll do it. You can't smoke in public wherever you want.
Manny countries have laws against smoking, but some cities and states in the USA have the most strict smoking rules in the world. In most cities like New York, Chicago, Seattle, San Francisco and Washington DC it is prohibited to smoke in bars, clubs, restaurants and other public buildings like shopping malls. California is even going a little further and bans smoking from beaches and in parks.
Always ask you companions if the don't mind you smoke. It's a form of courtesy.