"There is nothing either good or bad, but thinking makes it so." - Hamlet, Shakespeare
Oh...did you mean favorite quote from a TV show?
Then I choose:
"There's no God, there's no higher power. There's just chaos, and violence, and random unpredictable evil that comes out of nowhere and rips you to shreds." - Dean, in Houses of the Holy.
I love the way this is delivered. I love the setting and the lighting of the scene. I love the idea that Dean believes this (or believed it). It makes one wonder why it took him 3 more years (and a trip to hell) to completely lose faith in the entire world. He had already isolated himself way back here - a lone force for good against a sea of evil, with no allies except a brother that he may ultimately have to kill. More than that, it's Dean admitting that he has been ripped to shreds.
If I hadn't already been hooked on the show at this point, this line would have done it for me.
Part of me kind of wishes that they hadn't brought in the angels, just so that Dean would have never been proven wrong. I found the idea that someone could have solid proof of the existence of Hell and demons and yet deny the existence of Heaven and angels. That being said, I love the fact that in the end, Dean just says that he's coming for God next - he may have his proof, but God just turns out to be another chaotic element that ultimately rips Dean to shreds.
I guess I love world-view that these two sentences set up - the idea that Dean is ultimately fighting a losing battle and he knows it. It's him against a swarm of evil with no salvation after he dies.
Here's something funny to counter-balance that:
My favorite quote from a convention:
Question (paraphrased): "I've noticed that Supernatural has a lot in common with Japanese horror films...and I was wondering what movies influenced you from that great genre of Japanese horror?
Jared: "Oh, horror!" *looks relieved*
*Kripke cracks up*
*Jared blushes and hides under the table*