Reference to the region of Oklahoma that uses the 580 area code. It covers the remainder of the state not included in the Oklahoma City or Tulsa areas, including Lawton, Enid, Ponca City, Altus, Frederick, Weatherford, Guymon, Durant, Ardmore, and most importantly Fairview (the hardest of them all).
Area code 580 was created as a result of a split from area code 405 on November 1, 1997.
The Shady 580 is given the least amount of respect because of it's generally small population, hence the "Shady", however, is nonetheless a force to be reckoned with.
405: "Dude, you holdin' it down in the Shady 580?"