Sir Isaac Newton - "I can calculate the motion of heavenly bodies, but not the madness of people"

Few had known that Sir Isaac Newton invested in the shares of South Sea Company and lost money. The Company primarily did slave trading with South American countries. With great promise of prospect, people started snatching up the shares and pushed the price ridiculously high. It seemed like an easy way to get rich quick and more people get into it by paying more and more. The Company proved to be unsuccessful and in the end, its shares plunged and became worthless.

Thus, we learned that even a genius mathematician like Sir Isaac Newton could not predict the stock market. It isn't easy as there is an element of human psychology (greed and fear) in the price determination of shares and it is almost impossible to calculate.