Found on the "Damn Interesting" website
What has reality done for YOU lately?
A very interesting look at delusion and sanity.
In one of Terry Pratchett's books we are introduced to Klatchian Coffee, a brew so amazingly potent that it will bring a drunk back cold sober almost immediately. The danger is that too much will actually take the drinker out the other side, to a state called "knurd," where the drinker sees the world with such cold clarity and lack of illusion that he goes nuts.