Read Hofstede's "Exploring Culture", and consider that a person in a high-collectivity culture, which also is a high-power-distance culture, may well answer the survey with what "face" requires them to say, instead of answering with what they, themselves, feel.

If you aren't correcting for that, you're doing propaganda, not science.

Different cultures REQUIRE different subjectivities be taken-into-account.

I think it would be more valid to dig into specific dimensions of happiness, & make some of those objective ( cortisol-blood-levels, for measuring stress, e.g. )

WHEN you ask people in individualistic cultures a question, and THEN you ask people in collectivist cultures the SAME question, they are not answering the same question, they are answering the social-pressure question, instead.

It makes complete mincemeat of cross-cultural measuring of "objective" things.

Try reading Lanier's "Foreign to Familiar" book, & understand just HOW different warm-vs-nordic cultures are, in instinct/reactions,

then it should be more obvious how such surveys are disinformation, not information.