Finger Tips
Giving "the Finger"
In the United States, when you take all your fingers, make a fist and pop the middle finger straight up, this is known as "Giving the Finger". The middle finger gesture is commonly used by individuals who are not exactly near each other to get a message across. This message is in essence, they don’t like you or something you did. If you’re old enough to drive, you’ve probably seen this gesture a few times. Heck, you may have even used it yourself a time or two – maybe even as a joke with close friends.
Western Culture
In most western cultures, and in the U.S. specifically, the middle finger is used fairly loosely, often times misunderstood by people outside of our country. Americans use it to yell at people without saying words and in a joking manner when you just want to tell someone to bugger off (as Europeans might describe it). In other countries around the world, other fingers are
used to pass the same message along. So if you’re visiting Iran for example, you may want to be careful about giving someone a "thumbs up" for doing something good – because they’re going to think you’re giving them "the finger". When giving some the finger in Iran, if you stick up your middle finger, they won’t know what it means. Why? Because Iranians use what we perceive as a good finger gesture to tell someone to bugger off.
In Sri Lanka, it’s the index finger that really gets people going.
In New Zealand, Australia, India & Ireland, what we 
perceive as a peace sign, can be misunderstood as an obscene gesture as well.
What these differences outline is the danger of using the finger in general. When using "the finger", know where you’re at so you know how to tell off that person who cut you off OR so you don’t use it when you didn’t intend too. No need to get anyone mad at you when you meant no harm in the first place.
Another item worth noting is that most cultures outside of the United States do not take the use of the finger as a joke, so be wary of how and when you use the finger – whether it’s the thumb, index, ring, middle or little (pinky) - it may be best to keep your hands to yourself when traveling.
search for more information about finger gestures, american sign language, and hand signals
