If your first paragraph was true, wouldn't people continue to feel happy but just not show it? I feel like unhappiness must be adaptive (even without considering social effects) at least in some cases.
That gets into Hansen's theories about hypocrisy-- sometimes it's easier to believe the mask one is wearing is one's real self. And this overlaps what Vassar has said (as I understand him) about some people trusting what society says about what a person ought to be, rather than taking the light and flexible approach to language that the majority of people do. (Translation: being a geek can be being a sucker.)
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
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