[twofornone]

Do you have a source for that? Happiness I can believe, especially because of the correlation between intelligence and neuroticism, but if IQ is a valid proxy for intelligence then I think the consensus is that intelligence strongly correlates with success.

[hackernewds]

High IQ people are also thought to be prone to ambition, questioning for purpose and stricter yearning at any achievement level which leaves them perennially unsatisfied