If you are traveling to a foreign country, be sure to familiarize yourself with the local customs before you go. This will help you avoid any embarrassing faux pas. It will also help you integrate into the culture a bit better.
For instance, in India you should not offer anyone your left hand for a hand shake. The left hand is traditionally used to clean yourself up after a trip to the toilet; therefore, offering your left hand to someone is a disgusting insult.
You should also try your best to dress accordingly with the native inhabitants of wherever you are visiting. For instance, wearing a tank top and a miniskirt is an extreme no-no in India, no matter how hot it is.
To understand why, read up about Indian culture before you go. Learning about a country's culture will help you get more out of your trip!