There really is only one foreigner I used to 'lunch' with on occasion when he was in Thailand. A fellow American with mainly shared views on the state of the world. He, on the other hand, had a wide variety of farang characters for friends, one being the alcholic golf pro and another a big lawyer for some foreign firm who lives in some 200K baht per month condo near the US embassy. Once he convinced me to grab lunch with this crowd and I was never so disgusted in my life. Topic of conversation were "Look at that 'slit' over there, maybe I should go over and 'pork' her for dessert (the golf pro who was drunk before lunch arrived), "I need to send my GF somewhere for an abortion, maybe Hong Kong, my wife ? ah...she doesn't give a $$$$ as long as her ATM card keeps working" (The rich lawyer guy).
This is why I tend to avoid foreigners in Thailand, it seems to attract the bottom of the barrel insofar as ethical behavior, and that just makes me uncomfortable. My friend thinks these guys are hilarious and maybe hangs out with them for their antics I guess.