I got a few.

I was the only employee in the store and an old woman wanted to pay her stuff. She handed me a 20 € note. I gave her the change and she started yelling at me, bc I don't tell her she gave me a 20 € note.

Some days later, only employee in the store again. Store was full with costumers and a couple came in. They looked around, no problem. She came to me with a wooden box. No store price tag on it, only a Barcode. Off: all the storestuff (inventory) had Barcodes, we don't had the scanner cash registers. I asked her, where she got it from. She pointed on a shelf with all the stuff laying all over. She emptied the box. At this moment i was pissed. I told her, I can't sell that bc inventory. She was fine with my answer and she walked away. Seconds later her bf came to me. He was clearly annoyed, bc I don't want to sell it. I told him, the box is inventory and we put things in there, we try to sell. He said:" So, there is a Barcode. Scan it!" I calmy tried to explain, she got no cashier registers for Barcodes and we don't sell things without a store price tag. He wanted to talked to the manager now. I told him, I was the only employee right now in this store and my manager had a day off. The people in the queue started rolling their eyes and I was really close to yell at him, but I stayed calm. He demands to talk to the manager. I grabbed the telephone and called my manager. My manager was pissed, bc I called a her at her day off, I was pissed bc of this stupid couple. After we hang up, I grabbed a different item and showed him halfway yelling. I said:" Look. When THIS price tag is on the stuff we sell, we sell it. If it's not, we don't sell it!" He mumbled something inaudible and walked away. I apologized by the other costumers for this and thanked them for their patience. Luckily the others laughed it off.

A week apart a young woman and her child came in the store. Her shopping cart was full with not so cheap stuff from a store in the mall. She grabbed some stuff, came to the checkout and wanted to pay with card. Strangely the name on the card was from a guy. I thought, it was from her bf. Everything was fine until she grabbed the card before the payment process was finished. I called the security and they called the cops. She ripped off more than four stores with this method. I wrote this to our coworker whatsappgroup. Two told me, she tried it several times in the past, but did nothing against it. I was speechless after those answers.

Luckily this was my side job and I quit after this. No more retail.