Not true at all: 1) more intelligent people are happier (author of the blogpost cherrypicked 2 studies, one of which in fact showed that iq is positively correlated with hapiness. 2) IQ negatively correlates with neuroticism. 3) In fact IQ correlates positively with almost every positive facet of human experience - https://www.pnas.org/doi/10.1073/pnas.2212794120