Cultural differences are what makes standardizing experiments very difficult. What is common and well understood in the US is foreign and confusing in other parts of the world. I found this video on hand gesture that would get you into trouble in other countries. This video is an example that words and gestures that are common in one part of the world mean something very different or even rude in another area. Acclimating oneself in what is appropriate in other cultures develops better interpersonal relationships.