I was a supervisor at Cost Plus World Market, a Karen comes in one night pushing a cart full of obviously used throw pillows and asks to return them. Of course she has no receipt, and instead wants us to just "look her up in the system". Except she refuses to provide her information for us to try to look her up. She starts yelling at my cashier and that's when I stepped in to tell her very politely and calmly that she either needs a receipt or needs to provide us her name and phone number. She starts screeching and screaming about how we're [idiots] and she'll get us fired and blah blah blah, then she demands an apology from the president of the world. I'm certain she meant the president of World Market, but in her bleached hair fury she said "the president of the world" and I barely held it together as I calmly offered her the corporate feedback number. She wouldn't take it and instead walked out of the store still yelling and without her cart of dirty pillows. She returned about 20 minutes later, quietly apologized, and took her pillows with her, we never heard from her again.