Receipt
Categories: Accounting
You bought a sweater at Macy's for $150. You even got a bag. As you're walking out the door of the store, that horrible alarm and a red light goes off. A security guard stops you and asks to look in your bag. You show her. And with kind of a pissy look on your face, you also hand her the receipt, clearly showing that you paid $150 via your AMEX, and that you are legit.
The culprit? That little magnetic plastic thing that the checkout guy with 5 cheek-earrings forgot to remove. But as you look angrily back there and see him smirking, you really wonder if he "forgot."
Anyway, since you kept your receipt (your physical or electronic documentation of your purchase), all's good.