This isn't a fault of the post per se, but I wish there wasn't so damn much equivocation on the word "happiness". I know what sadness, contempt, contentment, rapture, &c. are—introspectively they strike me as a rather distinct states. But "happiness" means like ten or fifteen different things that are only somewhat related to each other. (FWIW smiling makes me feel bitter-sweet, not happy, so this might be an undue generalization from one example.)

Also, at least many kinds of happiness are measures of value, not ends in themselves, and so chasing after them specifically is getting dangerously close to wireheading or the problems of Goodhart's law more generally.