The frog in the heated pot of water. Have you heard this? Of course you have. It's one of the most overused illustrative anecdotes ever, especially on very serious television news special reports. In case you've been trapped in an elevator for the past fifty years and you've managed to find this blog before the shock of the 21st century overwhelms you: a frog is sitting in a pot of water, which is slowly heated. The frog remains unaware of the gradual change in temperature, and eventually boils. And while you're thinking about dead, boiled frogs, stop polluting the environment/ferrying illegal aliens into the country/looking at porn on the Internet.
You guys. The origin of this story is really shaky. The experiment was performed over 100 years ago; an article that the Wik' article links to at the University of Georgia's ecol lab website states that frogs will jump out of the water when it gets uncomfortably hot, unless the scientist put it in a pot with really high sides and it can't get out. Dick move, scientist. But my point is: it's a big cliché, and it might not even be true.
We need a new metaphor to warn about the dangers of complacency. My suggestion: professional television writers get incrementally sloppier at their jobs until they're only capable of producing hackneyed crap aimed squarely at the lowest common denominator. SCARY! Watch your cholesterol.