6. Harvey Dent's Secret Is Unveiled
At the very outset of the film, we see Commissioner Gordon giving his eulogy at the funeral of Harvey Dent, and idolising him as a virtuous fallen martyr, as Batman intended. But for a brief moment, it seems Gordon will succumb to his conscience and read a different eulogy, confessing Dent's crimes and his own role in hiding them for the greater good. Ultimately he goes against that instinct and preserves the myth of the former DA, and continues the theory that Batman killed Dent's victims, keeping the other eulogy hidden within his coat pocket. That turns out to be an error of judgement as his first encounter with Bane in Gotham's sewer system leads to his capture and injury (explaining that early footage of him in a hospital bed), and Bane's discovery of the revelatory speech in his pocket. Slightly careless. Bane then uses the information to inspire the criminal and lower classes of Gotham to unite with his army to destroy Gotham and cleanse it of the corruption borne off the back of that great deception. That story detail also gives an extra dimension to Commissioner Gordon, who is haunted by the spectre of what he did, and to the outrage that inspires the Gothamite lower class rebellion. It's also an interesting extrapolation of Nolan's fascination with the dynamic between villain and hero, and how those figures are perceived by their actions from an external point, which underpins the development of John Blake's character towards his ultimate conclusion (up there at number 2).