My nomination for the scariest song:
http://www.you-tube.com/watch?v=GWKpblxejWE
To set the stage for why I chose it:
The song is based on an actual event that happened in 1966. At that time, the vast majority of families were modeled on June and Ward Cleaver (Leave It to Beaver). People lived with a general illusion of safety.
Woodstock had not happened yet. US combat troops had just been deployed the prior year to the Vietnam War, so it had not yet become the "ugly" war that it had by 1971.
The song had a big impact on me at the time. It's a fascinating perspective on a topic that people prefer to avoid.
