Some places have laws that are more lenient when it comes to drug use as well as drinking alcohol. There are also many places that have a legal system that is much stricter than what Americans are accustomed to.
Research is key when traveling:
It might sound like work-but when you are traveling to a foreign country; it is a very good idea to do a little research before going. You might find that the opinion about the location that you are visiting is quite different from what it is actually like.
For example: Amsterdam
Most people have this idea that in Amsterdam you can do just about anything involving drugs and prostitution, and there will be absolutely no repercussions. The actual facts are somewhat different though.
Legalities in the Netherlands:
Possession of under 5 grams of cannabis
Smoking cannabis in coffee shops (in Amsterdam).
Riding a bike without a helmet.
Many recreational drugs
Smoking (anything) in public places, other than coffee shops.
Smoking cannabis in coffee shops (in Maastricht, on the border) if you are a foreigner.
Riding a bike without a bell and a light.
Using a cell phone when driving.
Funky mushrooms (containing psilocybin) are illegal but are tolerated in small amounts.
Hashish is tolerated depending in the municipality that you are located in.
Coffee shops in Amsterdam and other places in the Netherlands will sell small amounts of Cannabis. It is also both acceptable and expected that customers will smoke in these coffee shops. Once you leave Amsterdam it is important to learn the regional laws. Some spots will allow tourists to buy and imbibe while their neighbors will not. Getting in legal trouble in a foreign country is absolutely always going to be more complicated that dealing with a similar situation at home.