Most of those complainers are leftovers, rejected, losers.
They got a divorce in their home country, being kicked off from wife/partner and family, unsuccessful in their former life, looking to start a "new life" in Thailand, believing the grass in Thailand is much greener.
However, running away from their problems, failing in any long lasting relationship, they are up to prostitutes, drugs and alcohol, bragging what exceptional heros they are. In reality poor midgets.