Absolutely no need to buy the book. Just read his original blog post that is more or less a TLDR; version of this bloated Amazon book. It made a huge difference in my work life. Everytime I found myself in a dumb user or arrogant dev or inept manager type situation (in meetings or emails or face-2-face), I would think back to this blog post and instantly feel better.

Mark Manson "THE SUBTLE ART OF NOT GIVING A F_CK" (12 minute read) => https://markmanson.net/not-giving-a-fuck