In high school I studied history and was amazed I suppose at this 10,000 year catalogue of human folly.
Then briefly I discovered economics and thought markets were rational. That lasted about a year, until I studied economic history (which I commend) and which is just another catalogue of economic folly, that Daniel Kahneman and others have more recently helped explain. I went through various approaches: Marxist, therapeutic, personal construct, psychology, and more recently neuroscience, and none of them really explained the sheer scale of human folly. And in the corporate world I experienced its growing spread once stock options and short termism took hold and value add activity became replaced by short term quarterly results spin.
But I guess none of this prepared me for the current level of folly where a free market fundamentalist ideology has been hi-jacked by special corporate interests and used to take over the government in many countries. This corporatism uses our growing knowledge of human psychology tested in the ad world to spin delusions about reality and control us. But it is done for such kamikaze, planet- destroying sociopathic reasons that it represents a new level of human folly. To paraphrase Winston Churchill: never in the course of human history have so many been duped by so few for so little purpose.