Adam Robinson has a talent for simplification. He has, for example, identified the key to happiness to be connecting with others, making them happy (paraphrasing), and always expecting miracles. I love his critique of the typical self-help book as being exactly focused in the wrong place: oneself.
He has also identified a set of common causes of being stupid, paraphrased by Shane Parrish:
When it comes to overloading our cognitive brains, the seven factors are: being outside of your circle of competence, stress, rushing or urgency, fixation on an outcome, information overload, being in a group where social cohesion comes into play, and being in the presence of an “authority.” Acting alone any of these are powerful enough, but together they dramatically increase the odds you are unaware that you’ve been cognitively compromised.