The Killing Joke.
Okay...I read my first Batman story and all I can say is that I fell in love...with Joker. All he wanted from his life was to make his wife and kid happy but at the end all he did was one wrong after the other. I'm not familiar with the Batman fandom-in fact The Killing Joke is the first DC comic I ever read-but Joker is like a modern age Oedipus. No, he's not marrying his mother and kills his dad but his life is equal tragic. Reading the story I felt like reading a Greek drama. What I liked the most was that even Batman wasn't acting like the superhero that he is; he was acting like a normal man, fed up from life and with no faith at all.
He, either would kill Joker or Joker would kill him. And the end is simple un-fucking-believable!