I can only agree; while a positive attitude is more healthy and might even attract (i.e. make you more receptive for) positive situations, it is not the "fix it all" and can in some cases even be detrimental.
The hype around the Secret scared me a bit; I have no idea whether it really is connected to Scientology on any level, but many of the statements have that negative ring for me (e.g. being responsible for "attracting negative things" to oneself etc.)