The main people that I felt were happy there were the chinese-thai in the chinatown area where the shopkeeping was done for generations, or a way of life, rather then just work. In fact, that's the area I would like to live in if I ever went back.
They have their own little insulated world in a strange way that I think protects them from the usual hassles and irritations most people would experience in bangkok. They are good at associating with only people in that circle.
Everyone else kind of seemed stuck there just for economic or employment reasons. There were a handful of retired expats that lived there long term, but they did not really seem happy to me. It felt like there were just there for lack of reason or drive to go anywhere else.
At least that's what I felt when I lived there, without bluntly asking people if they were happy 🤣.