It is annoying when people that haven't travelled show how ignorant they are with prejudiced answers.
To seriously answer your question, Chiva-Som International Health Resort in Hua Hin seized the top spot as the world's number one Destination Spa in a recent Conde Nast Survey while The Regent Chiang Mai Resort & Spa was rated the 9th Best Overseas Hotel Spa.
It is a huge industry and the massage therapists are no different than elsewhere. They are exceptionally well trained and it usually is a job for life.