Even if you have been to Thailand way longer than I have, I am a Vietnamese so I understand more about the Vietnamese social values and mentality. Which also means that when I see someone similar to my own people, I can identify them more easier and more quicker.
And the survey data has shown the Thai and Viet to almost be exactly in the same place. So my personal claim has merits. The survey does not consider trivial things like whether the people eat with chopstick or whether they celebrate a certain holiday. They ask more important questions that reveals the social values and attitude of the people.
OK this is a more serious reply. Yes my holiday experience is only superficial. But I have many personal Thai friends here, get invited to their house often, interact with their family and elders often. They are almost exactly like Viet. I have some Chinese friends too, and no, they have different social values and attitude compared to the Thai. Yes Chinese is quite similar to Viet compared to other ethnicities, but Thai are even more similar.
I dont care about superficial “cultural” stuff like eating with chopstick or spoon, celebrating certain kind of traditional holidays, form of govt, etc. Or superficial habits and civility like spitting on the street or refusal to stand in line, talk loud, corruption and disregard for civil law, etc (in this respect, China would be more similar to India than say, Japan). So habits and civility does not mean much to me in terms of “culture”.
I am more interested in looking at people’s attitude, social values, etc. when it comes to “culture”. And that survey supports my view. And my personal view is from a Vietnamese perspective.