I often read books like this one. They are spliced between fantasy fiction and biographies. I'm sure it confuses my friends but the truth of the matter is I have a strange interest in human behavior and abnormal personalities. And by strange I mean I need to understand it because more and more the people around me, for whatever reason, are exemplifying these weird behaviors,such as The Dark Triad (Narcissism, psychopathy, and Machiavellianism) and sociophathy. These people are not my loved ones, for the most part, just in case you were curious; they are associates, patrons/customers, and random people I hear about through the grapevine. This book by Wendy L. Patrick, Ph. D., analyses these personality disorders and diseases and how we as the well adjusted members of society often find ourselves involved with these people. It also discusses in detail how to avoid them.
Red Flags: How to Spot Frenemies, Underminers, and Toxic People is a well organized and clear cut dissertation on the subject of manipulators and how they can, and will, destroy your life regardless of how much you think you can change them. However, she also discusses how some people (undoubted the exceptions to the rule) can and do change from these poisonous personality archetypes. We shouldn't assume every well educated man in a suit is trying to control us and use us for whatever money and social status we may have acquired. However, she informs you of how to spot the ones who are malicious.
Another, and I'm sure unintentional effect of this book, was they way it forced me think of myself and my FLAGs. Am I presenting my best self to the world/Universe/humanity? Do I allow any of these archetypes to use me in such a way that is self-damaging? This book is an all around great read. If nothing else it will equip you with information to keep you safe from malicious people prowling to take advantage of you in any way possible.
Also she ends her book on a positive note. So don't worry about feeling depressed about humanity at the end.