Gross income inequality can cause a host of problems for a country. It inhibits social mobility, stymies the entrepreneurial spirit, and it ensures that the bulk of consumers on whom we rely to keep the economy moving lack the funds to meet many ends beyond those immediately related to their survival.
That the United States is terribly unequal (one of the most unequal of the developed nations) is no secret. But just how bad is it, really? The imbedded video provides a good video representation of the current state of wealth distribution in America.