How about this one:

I am legal to buy alcohol.
I walk into the packie, I buy vodka, I don't get carded.
I go to the car, put the vodka in the car, realize I forgot a bag of ice.
I go back into the store, pick up a bag of ice, go to the checkout.
The clerk that JUST rang me up for the liquor won't sell me the bag of ice because I don't have my ID!

WTF?