I just watched "The Dark Knight" in IMAX cinema.
I must say that it is a great movie. You can know it if you did follow my blog because I seldom wrote something about a movie except the movie is a really good one.

Joker is a briliant character in the story. He challenges the best cop in town to do things that people won't expect him to do.
To the clown prince of crime, a knife is preferable to a gun, the better to "savor the moment."
To him, beauty could be reborn in the midst of a living hell is just crap. Everything will getting selfish once the situation limit you to act generously.
He knows damn well that humantiy is what you will lost when you are trying to gain power.
So he creates this game call "humanity" test to "good" people
Even more important, perhaps, he believe that nothing can rise above the ugliness of the world around us. Even Batman himself.

A very good quote retrived from the movie
"The only morality left in the cruel world is only chance"

When there is no way for you, will you break a way urself?

Batman: You'll be in a padded cell forever.
The Joker: Maybe we can share one. You know, they'll be doubling up, the rate this city's inhabitants are losing their minds.
Batman: This city just showed you that it's full of people ready to believe in good.
The Joker: Until their spirit breaks completely. Until they get a good look at the real Harvey Dent and all the heroic things he's done. You didn't think I'd risk losing the battle for Gotham's soul in a fistfight with you? No. You need an ace in the hole. Mine's Harvey.
Batman: What did you do?
The Joker: I took Gotham's white knight and I brought him down to our level. It wasn't hard. You see, madness, as you know, is like gravity. All it takes is a little push!

The film itself evokes the collision of an unstoppable force with an immovable object.
The movie forces us to question our own value if we are facing similar circumstances as well

What will you choose then?
To kill others for your own sake?
Or to kill youself for the world.

That is, the question that Christopher Nolan leaves us to ponder with.

When desperate strikes, what left, is only selfishness
no matter who are you.

How good are you.

And even how holy are you.