The only thing that bugs me every time I watch the film is at the end of the bank robbery scene, where the Joker drives the bus out of the bank, surely someone must stop and think "hey, that ain't right!!". Just seemed jarring. Otherwise, I thought the film was brilliant. Well except for the final sonar scene, which confused me in the cinemas, but played out better at home.
Marge: "Oh no, how will the kids get home?"
Homer : "I dunno, internet?"
^Problem solving, Homer Simpson style.