We often assume that expressions like a smile mean the same no matter where we are in the world, but it's becoming increasingly evident than such communication constructs vary depending on the culture you're raised in.
BBC News reports on a study which suggested that interpretation of facial expressions in eastern cultures focuses largely on the eyes, while in the west the whole face plays a more important role:
The team showed 13 Western Caucasians and 13 East Asians a set of standardised images depicting the seven main facial expressions: happy, sad, neutral, angry, disgusted, fearful and surprised. They used eye movement trackers to monitor where the participants were looking when interpreting the expressions.
As well as impacting in-person communication, this difference can also be seen in the emoticons used in electronic communication. The classic 'smiley' you're probably familiar with gives about the same amount of space to eyes, nose and mouth :-), but the Asian equivalent makes the eyes more prominent (^-^).
Facial expressions 'not global' [BBC News]