Old Navy, Waterworks Mall. Just Before Closing.
A disheveled middle-aged woman walks up to the counter with a cart full of clearance merchandise. While ringing up the clothes, the cashier separates out several dog bones and rings them up:

Customer: Wait. Wait wait wait. Seventy-five percent off of $3.50 is not 97 cents. It’s…
[The woman quickly (and seemingly painfully) does the math in her head.]
Customer: It’s 88 cents.
Cashier: But the register tells me—
Customer: LET ME SEE YOUR MANAGER!
[The manager, who is a few feet away, approaches.]
Cashier: [Whispering to manager] She says that 75% off of $3.50 is 88 cents, not 97.
[The manager whips out a calculator, finds that the customer is right, and has the cashier change the price. The woman then continues to mentally figure out the price of each clearance item as it comes up to make sure that it is correct. Each item is wrong and her price was correct. The cashier finally bags her items.]
Cashier: Do you want the bones in a seperate bag?
Customer: No. I’ll hold them.
[Confused, the cashier hands her the several large dog bones which barely fit in her small hand.]
Customer: ‘having a small seizure] These are for the babies… the BABIES…. and they bark… and the babies… babies… BABIES… babies… bark…. they threaten… BABIES….
[She wanders off, rambling the entire way.]
Manager: [into headseat] We just had Rainwoman up in this shit, ya’ll.