emotional hopeful fast-paced

This book has the same style of pseudoscience psychobabble commonly popular through Malcolm Gladwell books. Much of the evidence are clear instances of p-hacking or outright speculation. As a result a lot of the conclusions make surface-level sense ("I'd believe that!") but fall apart on further reflection ("Wait that sounds dumb."). Examples include the correlation of introversion to blue eyes -- the author says Disney may have known that already by giving their princesses blue eyes -- and the tying together of introversion with volume of voice. Most of the facts are only defensible by references to scholarly articles that probably wouldn't survive a Retraction Watch review.

Overall, while there are some nuggets on how to handle mixed relationships, the book as a whole can be dismissed. I get why this book got popular: people wanted to believe it was true, just like Gladwell's 10,000 hour assertion that was fabricated and debunked. But it'd be better to find a book on extroversion and introversion that wasn't fake science. Wherever that book is, it's more valuable for your time than this book.