Banking is all about trust. We trust that the bank will have our money for us when we go to get it. We trust that it will honor the checks we write to pay our bills. The thing that's hard to grasp is the fact that while people are putting money into the bank every day, the bank is lending that same money and more to other people every day. Banks consistently extend more credit than they have cash. That's a little scary; but if you go to the bank and demand your money, you'll get it. However, if everyone goes to the bank at the same time and demands their money (a run on the bank), there might be problem.
Even though the Federal Reserve Act requires that banks keep a certain percentage of their money in reserve, if everyone came to withdraw their money at the same time, there wouldn't be enough. In the event of a bank failure, your money is protected as long as the bank is insured by the Federal Deposit Insurance Corporation (FDIC). The key to the success of banking, however, still lies in the confidence that consumers have in the bank's ability to grow and protect their money. Because banks rely so heavily on consumer trust, and trust depends on the perception of integrity, the banking industry is highly regulated by the government.