Some of these rules that you say are scams work for me and have changed my life. But some also don’t. Where the gurus promoting these ideas are selling snake oil is claiming that they work for everyone.

I wish productivity gurus took more of an “encyclopedia” approach of presenting many methods that have worked for others that you can try, rather than selling their entire system which probably only works for them. Learning productivity principles is only the beginning — you have to figure out what works for your personality, lifestyle, type of work you do, etc and it could take years of trial and error this way before you discover a half decent system tailored to you.