When Jeff Bezos wants to call his team's attention to a customer complaint, the Amazon founder and CEO forwards the email directly to his executives, with a note that consists of a single character: "?"

"That question mark is just a shorthand for, 'Can you look into this? Why is this happening? What's going on?'" says Bezos, speaking to the George W. Bush Presidential Center's Forum on Leadership in April.

Though Amazon has a market capitalization of almost $780 billion and Bezos himself is worth $132.5 billion, according to Forbes, the tech executive still has a customer-facing email address at Amazon, because hearing from consumers helps him identify pain points.

Honored to speak at @TheBushCenter Forum on Leadership tonight with Ken Hersh. The spirit of former First Lady Barbara Bush was very much felt at the event.

"I still have an email address that customers can write to. I see most of those emails, and I don't answer very many of them anymore but I see them and I forward them, some of them — the ones that catch my curiosity," says Bezos.

Two emails from CNBC Make It to Amazon seeking to confirm the email address were not returned by the time this story was published, but a March, 2018, post on question and answer board Quora revealed a shopper got a response when he emailed the alias "Jeff@Amazon.com." The Quora post includes a screenshot of the response from a member of the Amazon customer service team which reads, "Jeff Bezos received your email and has asked me to reply on his behalf." Business Insider also identified "Jeff@Amazon.com" as the customer-facing email alias.

Amazon measures countless aspects of its business with data, which is important, says Bezos. But it doesn't tell the whole story.

"I am actually a big fan of anecdotes in business," says Bezos.

"It's very interesting because we have tons of metrics. We have weekly business reviews with these metric decks," he says. "We know so many things about customers and whether we are delivering on time, whether the packages have too much air in them and [are] wasteful of packaging and so we have so many metrics that we monitor."

But, "the thing I have noticed is that when the anecdotes and the data disagree, the anecdotes are usually right. There is something wrong with the way that you are measuring it," says Bezos.

"You do need the data, but then you need to check that data with your intuition and your instincts. And you need to teach that to all the senior executives and junior executives, too," the billionaire founder says.

Bezos is famously customer-obsessed.

In his annual shareholder letter, released in April, the Amazon boss says customers are "divinely discontent" and their ever-rising expectations keep Amazon having to improve and innovate quickly.

"Their expectations are never static — they go up. It's human nature. We didn't ascend from our hunter-gatherer days by being satisfied. People have a voracious appetite for a better way, and yesterday's 'wow' quickly becomes today's 'ordinary'. I see that cycle of improvement happening at a faster rate than ever before," says Bezos in his annual shareholder. "You cannot rest on your laurels in this world. Customers won't have it."

Recently, an email to Bezos' customer-facing address resulted in an unusual customer service win — the happy reunion of a dog with its owner.

Businessman Richard Guttfield discovered his black miniature schnauzer, Wilma, was missing after a driver delivered a package of dog food from Amazon.

"My puppy went missing after an Amazon delivery and after an email to Jeff (Bezos)… we had someone who was amazing who tracked the driver and found our dog and brought her home," Guttfield told CNBC.

See also: