The concept and thought behind the book are great and I'd love to see more like this. Some science, psychology, etc. and more about what it does to you and what small steps you can take to change. There isn't blame in the book either, which makes it less of the "you are a bad person" and moe of the "everyone is broken and it's okay".
What I don't like and why I gave it three stars, 1) so much bad editing and 2) the book was hard to follow at times/some topics were beat into the book repeatedly. You ended up reading many sections on gratitude instead of just one. I also didn't like the artsy pictures at the end of chapters/sections.