To understand cross cultural social behaviour, you have to first make sure you are looking at behaviour in the context of not only the players, but their social environment.
Particularly in America, which has been the melting pot of cultures for generations, we take for granted that the behaviour in one culture must be OK for the other.
It may be true if you are dealing with the players who have grown up in both cultures.
Another complication is the support group around the players.
Let us therefore examine how social behaviours are to be evaluated between two cultures.
A few preliminary questions to ask:

1. How familiar is the person you are dealing with, with your culture?
2. Who all are going to or likely to get involved in your individual relationship with the other person.
   Is it just, for example a business transaction where family is not involved, or a more personal transaction like dating?
3. What are the "openings"--I will explain later
4. Who leads and who follows?
5. Is there money involved?
6. What are the "exits"--I will explain later
7. Is there a dynamic other than the immediate relationship?

Depending upon a particular situation, other questions may have to be asked and answered to the satisfaction of both players.
Now let us study some general behavioural traits.

• Do not overstep common sense decencies.
  E.
  g.
  in some cultures like India and Thailand, talking above normal decibel range is very common.
  That is because most Asians grow up around noise.
  Their houses are usually open to the streets, offices are not sound proof.
  So you will find that they talk very loudly.
  If you belong to that culture, beware.
  Do not automatically turn up your sound unless you are sure the player on the other side--girl friend, acquaintance, colleague, business partner--is also from that culture.
  It is not enough for him or her to be just familiar with your cultural eccentricities.
  He or she must buy into them.
  If not, use common sense.
  
• Take it easy and slow.
  Aggression in a cross cultural relationship is not prudent.
  E.
  g.
  some European countries believe in what is known as "zip-zip" relationship pattern, whether in business or personal front.
  
• "openings" to conversations and initiatives are very important.
  In the US conversations usually begin with what are called ice-breakers.
  Ice-breakers are never too personal, but about subjects that are neutral, such as sports, personalities, weather etc.
  In the Asian culture, ice-breakers can be about politics or something more personal, like relatives, family and elders in the family.
  When some one asks you how your mother is, he or she expects an answer, not just "OK".
  In some Muslim societies, religion can be an ice-breaker.
  It would be taboo in America to ask someone which Church they belong to.
  
• Body language is extremely important to all cultures and each culture differs.
  Generally, western cultures do not make excessive use of gestures, hand signals or faces.
  Asian cultures do.
  Do not be offended by it.
  

So be sensitive, but always use common sense in understanding standards of social behavior.