I read Seligman’s Authentic Happiness some time ago. He has an interesting hypothesis. The idea is that the negative emotions (fear, envy, greed, etc.) are about scarcity (win-lose) while the positive emotions are about more collective constructions (win-win). It is a bit difficult to discern which ideas in this book are well validated by good studies; it appears that this idea is closer to the insta-theory end of the spectrum than most. But I like it. Collective good, selfish bad.
Even if you can puzzle out exactly which ideas and techniques he suggests are well tested you still get difficult confusions between cause and effect. Happy people have larger social networks, but how can you tease out the causality? In another example; it is will known that marginal increases in your wealth have a weak but positive correlation with happiness. That weak link suggests we ought to strive to earn more. Much less widely reported though is the trajectory of happy people tends toward higher wages and positions. I think that a cheery affect tends to generate the wealth, not the other way around.
The studies did show some interesting effects. Your various traits (humor, punctuality, cleanliness, etc. etc.) do tend to be genetically inherited and they don’t tend to be strongly effected by circumstance. I particularly liked that they know that older siblings do often have higher IQs than younger ones. How much? One IQ point!
He has a few pages devoted to dismissing the Freudian idea that childhood trama creates an emotional blockage which latter blisters out in ugly behaviors. Those ideas have been extensively tested and they came up wanting.
The Freudian idea that emotions are like water, e.g. if you represses them up they will leak out elsewhere turns out to be extremely wrong. Repressing is fine, and effective. Bottling up doesn’t cause them to stew. No, stewing on them makes them fester. If you nurture a grudge you can turn it into a monster. Living with those is a bummer. If you nurture gratitude, satisfaction, forgiveness, confidence, optimism, etc. etc. you can fill your inner life with kittens.