Ethan Siegel writes in his article  about how we cannot be experts in everything and how we are easily fooled by others and by ourselves.
“We like to think, as human beings, if we can only keep an open mind, that anything is possible. That if we put our minds to it, buckle down and do our research and apply ourselves 100%, we can not only understand what’s going on as well as any expert, but that we ourselves can make valuable contributions to whatever field we’re interested in. “… http://www.forbes.com/sites/startswithabang/2015/11/08/the-em-drive-nasas-impossible-engine-highlights-our-greatest-failing/
I don’t have much to add to what he says. I just wish people would understand, that while positive thinking may be important, it is equally important to practice skeptical thinking.
To avoid being fooled, if you care.
The reader comments of Siegel’s article highlight very clearly, that people actually often prefer fooling themselves, than thinking straight.