I think poor Thais are happier than most Westerners. They live with less but less stress too. I remember seeing a survey that talked about Norway, Finland etc being the happiest countries - but the cited education levels and medical care - they really didn't talk about happiness.
At the time I was in Hua Hin - the Skandis were on vacation walking around stone faced - and the Thai motorcycle taxi drivers who had nothing were laughing and playing with each other - having fun.