That old store manager told me to 'just smile and nod' at the angry ones. He was dead wrong.
I worked at a big box hardware store in Cleveland about 8 years ago. My manager, Jerry, a guy with 30 years in, told me to just smile and nod when customers got loud. Don't argue, don't explain, just take it. I tried that on a guy returning a half-used bag of concrete mix, no receipt, and he screamed at me for 10 minutes straight. That approach made him think I was ignoring him, so he escalated to corporate. Next time, I just told a customer straight up 'I can't take this back without a receipt, but here's a store credit anyway' and he calmed right down. Jerry's advice only works if the customer wants to vent, but most of them want a real answer. Has anyone else had a mentor give you advice that backfired like that?