After examining a lot of self-help stuff for a long time, my conclusion is that 100% of it is 100% bullshit. I have never, I mean never, ever, seen someone turn their life around as a result of reading a self-help manual. The only people I've seen benefit from it are the authors.
Self-help panders to the common desire to get something difficult with little effort. If "positive thinking" or any other BS worked, then you would see lots of readers of these books go onto success. But you don't. Most people who read these books are losers, and remain losers after reading god knows how many of these worthless tracts.
There's also the inconvenient fact that most successful people got there without even reading self-help manuals, let alone following the advice therein. Many very successful people are pessimistic, disturbed, unhappy, negative, undisciplined, lazy (outside their main field of success), and possess various character flaws. Perfect example is Winston Churchill - a clinical alcoholic and manic-depressive who rarely got up before noon. Look around you at successful people you've seen - they often have bad habits, problems in their lives e.g. smoking, drinking, bad marriage, overweight etc. This idea that success comes from being positive and an all-round hyper-disciplined person is BS.