The author of that book teaches the single most popular class at Harvard.
The field of "positive psychology" is maturing, developing real scientifically-backed theories on happiness and personal development. (a unignorable aspect of this, of course, is financial well-being, which is why many of us are here on news.YC)
If you're not doing what makes you happy, and have no plans nor desire to get out of this vicious cycle (I know, I've been there), then you will just keep spreading unhappiness to those you touch around you. (we all know someone who's constantly whining and complaining about things & being a constant downer to everyone)
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