Bank owners and bank regulators oftentimes simply did not fully understand what these instruments were, how they were traded, and the jaw-dropping risks that were piling up for the system as a whole. On the regulatory side, dangerous vulnerabilities appeared as well: a lack of attention to systemic risks in the financial system, and an over-reliance on markets to self-discipline.
In other words, complacency kicked in. One of the most important factors triggering the global financial crisis of 2008 was that in the previous years housing prices in the United States had stopped rising. In the 7  absence of these many vulnerabilities, this might have had only minor consequences.