In the United States, leaving tips to show our appreciation for good service in restaurants, bars, hotels, and taxis is so commonplace that, for most of us, the hardest part of tipping is making sure we carry the one and do our math right. But for Americans traveling abroad, unfamiliarity with local tipping etiquette can leave us feeling confused and paralyzed. Your best bet, if you'd like to be a culturally sensitive traveler, is to familiarize yourself with tipping customs before you travel so you feel more comfortable while you're abroad and so you don't commit an unnecessary social faux pas.
Geographically, all of Europe covers roughly the same surface area as the United States, but the multitude of countries within the continent means that tipping practices vary greatly from region to region, and your ability to get a one-way car rental in Europe means could you easily pass through a number of different countries during your stay. In general, service people like servers make a higher base salary than in the US, so you generally tip a smaller percentage of the bill; five to ten percent is typical in many countries. In Europe, you run little risk of offending someone if you leave a higher tip, so if you're pleased with the service and would like to tip the way you would at home, feel free. The exception is the Scandinavian countries, where cultural norms leave little room for ambiguity or personal choice. In Scandinavia, the gratuity is either included in the bill, or you don't leave it. In hotels, leave porters about a Euro per bag, and don't hesitate to leave the cleaning staff a little something at the end of your stay.
Latin America has traditionally been less of a tipping culture; however, American culture and throngs of American tourists are slowly starting to transform local norms. Unless you are in a heavily touristed area, tipping is not commonly practiced, but workers still appreciate tips even if they don't expect them. Leaving about ten percent is quite generous in many places, but if you dine in more exclusive, Americanized restaurants in big cities, you should expect to tip 15-20%. In Latin America, always check the bill before you leave the tip on the table; many establishments include the propina in the cost of the meal. If you get a rental car in Mexico, gas station attendants will most likely fill your tank for you; tip them about five pesos per fill-up.
It can be hard for Americans to come to terms with this, but it's important to know that in some countries, leaving a tip can come across as rude and offensive. Traveling and renting a car in Japan may be easy, but remember that their society is very different than American society. In fact, tipping in Japan is perceived as insulting, so as hard as it may be for you walk away from a table without leaving a few yen, try to be culturally sensitive to the people that are hosting you in their country. In the islands of the South Pacific, especially for people who come from indigenous tribes, visitors are seen as honored guests that should never be expected to leave a tip. China is also generally a no-tipping culture unless you're in a luxury resort or another area frequented by tourists; if you leave a tip in a tourist area, do so discreetly and away from the higher-ups. Before traveling in Asia, it's especially important to familiarize yourself with local tipping customs so you don't offend the service people that are doing their best to take care of you.
Although countries around the globe have had their own unique tipping cultures for quite some time, all visitors should, when in doubt, take a look around and observe what the locals and other tourists are doing. As Westerners and particularly Americans travel more frequently to certain destinations around the world, the influence of the tourism industry can begin to change local tipping customs. Asking a service person whose wages might depend on gratuity whether you should tip or not comes off as crass and can make someone uncomfortable, but feel free to inquire other locals who don't stand to benefit from your generosity what is common in their culture. In the end, if you're inquisitive without being discourteous and sensitive to local customs and traditions, you're sure to be well-received, and locals will notice that you're asking questions and making an effort to do the right thing.