Most financial crises have plenty in common: they tend to start in the banking sector and involve excessive borrowing, together with an asset bubble. The global crisis of 2008 was no different, with the asset bubble focused on US real estate. But my research suggests this crisis had another underlying cause—that some people in the banking sector were playing or "gaming" the system for their own financial gain.
The game being played had several important features. The first was the deliberate complexity of the financial products at its core. Then there are the behavioural biases that permeate decision-making at all levels of the banking industry. Banking often attracts people with certain personality traits, including those who are overconfident and take excessive risks.
Such people tend to like complexity for its own sake, but they often do not fully understand the implications of that complexity for the stability of the financial system as a whole. Often they do not care—they are primarily interested in gaming the system to maximise their bonuses.
The next element is risk. There are parts of the banking sector that will always be prone to risk, but many bankers have come to feel immune to its potential impact, because they presume that, however recklessly banks behave, governments will always be there to bail them out.
Gaming in the banking sector seems virtually impossible to eliminate. The only effective measure to end it would be to make bankers personally liable for losses, but no government has ever passed such a law, and no single government could do so on its own, since this would immediately cause their entire national banking sector to move wholesale to another jurisdiction.