Well, neurosciences tend to find generally good correlations between what people say they feel, and what can be measured by other means (IRMf and so on). Plus,

Well, neurosciences tend to find generally good correlations between what people say they feel, and what can be measured by other means (IRMf and so on). Plus, it seems human minds is completely sensible to auto-persuasion with methods as trivial as daily individual "say it loudly" and "visualize the situation has you already succeeded in the goal". So being completely acculturated to a social belief of "we are so happy in our land" can surely be granted some favorable credits.