Ten years ago we spent a bunch of time and money on the Y2K problem. While it is impossible to know if there really would have been a problem at the change over from 1999 to 2000 -- the consensus at this late date is that we dramatically overstated the problem, and dramatically overspent on the solution.
Our military regularly overestimates the size of threats in an effort to bring about a response; either in terms of funding for the military or outright action. We know some form of this played into the Iraq war.
The financial bail out of 2009 was identified and addressed by same people, and those people were tied very closely to Wall Street.
Large food companies have boosted sales of their products, particularly in developing nations, through misleading marketing. So much so that the World Health Organization had to create guidelines to discourage the practice.
Our pharmaceutical industry routinely convinces us we are sick and then sells us the cure. They are now busily convincing the rest of the world that they are sick too.
We all need to be wary of anyone who both dispenses the diagnosis and profits from the cure.