Benn pondering the same for years Marc..At one time an old thai told me, that Thai's generally go about things in daily life, trying toget the most fun out of it......
But i have also meet thai's who has very, excuse my language "shitty" jobs, and still i could get a smile out of them, when aproching in a friendly manner.
Maybe its just their way of dealing with things, instead of a frown and sour look, give a smile and recieve one back
Allthough i think there is more to it, religion, culture and so on.