Indian head wiggle

A friend of mine in this post points out the almost reflexive tendency of people in the western world to say ‘hi, how are you’ and walk on before you have a chance of answering this query. It’s quite hilarious actually. When I was in Australia, people did this all the time. You are walking on the road and happen to look at someone the same time he/she looks at you. Almost instinctively, out pops the question. I think this question is the vocal equivalent of the Indian head wiggle. In Sharjah and for that matter, in most of the Muslim world, the head wiggle or the 'hi, how r u' are substituted with a 'salaam alai kum', and since it is incumbent for a muslim to reply with a 'walikum salaam', people wait just that fraction to catch the reply.
Gregory David Roberts states in ‘Shantaram’: “Gradually, I realized that the wiggle of the head was a signal to others that carried an amiable and disarming message: I am a peaceful man. I don’t mean any harm.” (Pg, 107)
Ditto for the ‘Hi, how are you’ and 'salaam alai kum'.