Bezos, now the world’s second-richest man with a $159 billion net worth, reminded his followers of his humble origins with a tweet Sunday. “My first job. And still the same great burger. Happy Sunday!” he wrote, attaching a photo of himself eating a McDonald’s burger with fries. 

It’s not the first time Bezos has been open about working at McDonald’s, which began because he needed a summer job. His father worked there at a young age, too. In interviews over the years, Bezos has remarked on how flipping burgers helped him learn managerial skills, gain responsibility, and have fun.

His time at the chain started with a bang, he told Cody Teets, author of Golden Opportunity: Remarkable Careers That Began at McDonald’s. “My first week on the job, a five-gallon, wall-mounted ketchup dispenser got stuck open in the kitchen and dumped a prodigious quantity of ketchup into every hard-to-reach kitchen crevice,” he said. “Since I was the new guy, they handed me the cleaning solution and said, ‘Get going!’”

His McDonald’s manager was excellent, he told Teets. “He had a lot of teenagers working for him, and he kept us focused even while we had fun.”

He added that he was a strictly back-of-house employee throughout his tenure and never worked the registers. “The most challenging thing was keeping everything going at the right pace during a rush,” he said.

It taught him that customer service jobs of all kinds are “really hard,” he told Fast Company in 2001. “I was a cook. They wouldn’t let me anywhere near the customers. This was my acned-teenager stage. They were like, ‘Hmm, why don’t you work in the back?’” 

The burger-flipping didn’t provide much in the way of practical skills, however. He added that one of the great gifts the job gave him was the ability to crack eggs with one hand.

“My favorite shift was Saturday morning. The first thing I would do is get a big bowl and crack 300 eggs into it,” Bezos said. “One of the things that’s really fun about working at McDonald’s is to get really fast at all of this stuff. See how many eggs you can crack in a period of time and still not get any shell in them.”

However, some may say that Bezos didn’t necessarily implement all he learned during his time at McDonald’s when he became CEO of Amazon. Critics and legislators have repeatedly accused the business of treating its warehouse and delivery workers unfairly and dangerously. In 2018, author James Bloodworth went undercover at an Amazon fulfillment center and reported that warehouse employees were written up for any kind of breaks, including to use a bathroom. Amazon has denied this, but many workers have confirmed it, and numerous Amazon facilities across the country have filed for union representation.

But Bezos considers his experience valuable. He told Teets he encourages young people to work in jobs such as a McDonald’s line cook.

“You can learn responsibility in any job, if you take it seriously,” he said. “You learn a lot as a teenager working at McDonald’s. It’s different from what you learn in school. Don’t underestimate the value of that!”