In "Liar's Poker," Michael Lewis explores how groups of people, especially in finance, can easily convince themselves of the wisdom of their actions. This phenomenon often arises from the collective mentality that larger groups can foster, leading individuals to overlook doubt or poor judgment. As the numbers grow, there's a tendency to believe that the actions taken are inherently smart or justified simply because many are participating.

This self-delusion can result in risky behaviors and decisions that might not stand up under scrutiny if evaluated on an individual basis. The belief that one is part of a smart collective can lead to a disconnect from reality, causing people to engage in practices that may ultimately be detrimental. Lewis illustrates the danger of groupthink in high-stakes environments, emphasizing that the number of people involved can cloud judgment and obscure the truth of a situation.