5. The Joker Applauding Commissioner Gordon was Improvised
As spontaneous as Heath Ledgers performance looks, close study of the script makes it apparent that the Joker, along with every other element of Dark Knight, was very tightly written; Ledger brought the mannerisms and vocal quality to the role, but the words themselves are 99% on the page. One little moment of inspiration that Ledger did add came on the set of the scene when Joker is being held at MCU; when Gordon is named Commissioner, his fellow policemen applaudand Joker begins clapping too, mockingly. Jokers clap was apparently a completely spontaneous moment of inspiration; Nolan had to quickly tell the camera crew to start rolling again so that they could capture the improvisation, spur of the moment.