A well intentioned book.
I read this book hoping to be able to change myself. Unfortunately, the people this book hopes to change are people with much more serious problems, eg gambling, cheating, smoking, whoring, bullying, etc. Some of the advice could work based on the situation; however other advice is quite manipulative or naive.
I have always found honesty (and impartiality) to be the best way to deal with problems; passive-aggressive bs rarely works unless you're dealing with someone who probably would have responded even better if you had been honest with them, in a truly non-judgemental way. The one trick I did find funny and perhaps useful was the superiority complex way of dealing with people who put you down.
Much of the advice requires background attitude which isn't really explained very well in the book. For example, if you pour out your milk for a bully, they'll probably laugh at how well trained they have you. Also, a lot of the advice will result in bad kick-back from people with strong opinions who can detect manipulative bs.
Perhaps I come from a lucky background, and have continued to make my luck, but I feel like most of the problems either can be solved more simply, or aren't necessarily possible or worthwhile to solve.
Unless you have someone who you can't get rid of who has a serious problem, this book isn't worth your time.