In Asia, westerners are the minority and in many parts, you may see hardly any 'Whities'.
Consequently, when you do see a fellow tourist, you feel compelled to acknowledge them and perhaps, find out if they are from the same country as you.
When walking around, you can spot a 'Whitie' from about one hundred meters away like a milk bottle in a coke fridge. (this is also made easy by the fact that you are 2 feet taller than everyone around you).
Usually, you make eye contact at the same time and each person's eyes light up as they think the same thing... 'Hey, another Whitie!'
Then you look away cause you don't want to seem to eager and contemplate talking to them.
You both look back up at the same time and give the token head nod but that is as far as it goes. You never want to be the one that looks like the needy tourist that misses home.
As u get closer, you look at each other out of the corner of your eye, hoping they will say something and you can pick up on their Aussie accent and reminisce about home.
But alas, you both keep walking and pass each other wondering where they were from until you see the next 'Whitie'.