I learnt how to analyze characters, and that even though first impressions count, my judgement on a certain character should not be solely based on that. In Joker's case, I think that he is hyper-real; that he is what happens to a person when they lose everything they care about all at once as opposed to a slow and systematic loss where the time lapse between losses allows the person's sanity to recover and re-assert itself before the next hit comes. Because the human mind is a very fragile thing, built like a pyramid latticed deck of cards. When you remove the foundation, sanity comes crumbling down. The Joker's obvious lack in mental stability led to his decision to become a villain. In Batman's case, even though he was supposedly the hero, the means he used to track down the Joker shows that the two have many similarities. One of these similarities is that the two are ruthless when it comes to getting what they want. And the thing that separates the two is their intentions. Batman with good ones and the Joker with bad.