When people have asked me my thoughts about this movie (as I am both a huge Batman nerd and a psychologist), I tell them: I don't like it as a movie about mental illness, its not the right message and its not helpful. I really like it as a movie about the Joker. Go see it as a Joker movie, not a movie about mental illness, because it's not.

The message of the movie shouldn't be: "Take better care of the mentally ill so that they don't start an uprising and kill us all." I really despise that message, and can completely understand why people wouldn't enjoy the movie if that is what they got from it. I can also see why many people got that message from the movie. If you simply substitute "Joe" for "Joker", that's exactly what its about. However, the mentally ill are far more likely to be victims of violence than perpetrators of violence. So its not a good message.

But if you want to watch a tale of one extreme case of the development of one of the most vile and terrible supervillains in modern fiction, then its an interesting story, and the very final scene captures the character perfectly.