That sounds strange, but please drill some holes into my argument.

I would expect that unhappiness stems from the negative mismatch of one's expectation vs experienced reality. This, to me, implies that they had an unnaturally (and unjustifiably) high expectation of what reality has to offer. Additionally, it implies lack of understanding of WHY things are "bad" in the way they are.

You might argue, oh, they are smart only in a very narrow field, but then that sounds like learned helplessness for everything else, something a smart person should easily escape from.

None of this sounds like these people are actually particularly smart, or rather, it seems poor choices have been made in the beliefs they themselves or others apply to them, and now the consequences come back to bite them.

> unhappiness stems from the negative mismatch of one's expectation vs experienced reality

A juvenile unhappiness perhaps so. I would suggest adult one may stem from deep understanding how this world is built, altogether with futile attempts to change it.

Its taking all things as they are, and yet being sad exactly for the way they are.