I know -- there are dozens of these already, but I couldn't resist ...
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You've never met any celebrities....other than Fred Thompson
"Vacation" means going to the family reunion.
You know all 4 seasons: Almost Summer, Summer, Still Summer and Christmas.
You laugh when people from anywhere north of TN tries to say or spell "y'all"
It's "Mar-vull" not "Mary-ville"
It's "Knox-vull" not "Knox-ville"
A tabogan is a hat, not a sled.
You butter your hot biscuit by cutting it open, putting a slab of butter inside and closing it back up again.
Every town in East Tennesse has a "strip" and they're not particularly safe to be in at night.
Pigeon Forge is not pronounced with a French accent.
Gatlinburg does have an "L" in it and it should be pronounced.
Sales tax is 9.5%.
You shop at Walmart for groceries, not at a grocery store.
You don't drive in Knoxville on game-day. EVER. (SO TRUE!!! 
)
You or your friends chew.
You can't remember the last time you saw snow.
You have a "piss on" sticker on your car window
You know when Elvis Presley Day is
You actually get these jokes and pass them on to other friends from Tennessee.