On a stormy afternoon in Bentonville, Ark., a Walmart regional manager recounted a story about a moment when his humanity came up short.

He was 24-year-old store manager anxiously trying to get his workers to set up Halloween merchandise displays. Instead, the workers were gathered around the televisions in the electronics department. It was the morning of Sept. 11, 2001.

“Why are we over here not setting up Halloween? Why is it not done yet?” he recalled saying. He didn’t fully understand what was happening until a worker tearfully laid into him, explaining that she had relatives in New York City.

“I didn’t take a minute to survey the room to understand the ramifications of my words and my actions,” the former store manager, David Seymore, now a regional vice president at Walmart, told his listeners. “I grew up really fast that day.”

His remarks were meant as an object lesson. Mr. Seymore, who now manages 110 stores in the South and the Midwest doing $11 million in annual business, was speaking to a group of Walmart and Sam’s Club store managers who had come to Walmart headquarters for a leadership-training program that has taken place nearly every week at the retailer since July 2022.

Walmart and Sam’s Club store managers run multimillion-dollar enterprises and manage hundreds of workers. Their ability to drive sales has a direct effect on the company’s revenue, which totaled $648.1 billion last year worldwide.