Here's a few personal favorites:
1. All bodies of water in the South have horrible deadly monsters hiding in them - some of them are 12-foot long but others are microscopic.
2. Florida is not "the South". Florida is the only state in the Union where you have to drive 8 hours NORTH to get to THE SOUTH.
3. Yes we have seasons, but they go by different names - baseball, basketball and football.
4. The basic laws of mathematics are different in the South - everybody knows pies are round and CORNBREAD ARE SQUARED.
5. (Actually from the movie "My Cousin Vinny") - "If you didn't want grits then how come you ordered breakfast?"
(Pause here for groaning...

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