Wall Street collapse of 2007-2008

How did the filmmakers explain Wall Street collapse of 2007-2008?
Where, or on whom, does the movie place blame for the events leading up to the crash?
What are the rating agencies and what role did they play in the financial crisis?
Why did some outsiders foresee what would happen with the subprimes while neither the heads of the large financial firms nor government regulators saw what was coming?
What happen to those responsible for the financial crisis?
What was your favorite part of the movie? Who was your favorite character?
How good of a job, in your opinion, filmmakers did explaining financial crisis?
What do you wish they explained more? What do you still not understand and would love to know more about?