Elon Musk has never hidden the fact it isn’t easy being a Tesla employee. “Nobody ever changed the world on 40 hours a week,” the CEO has tweeted, noting 120-hour work weeks weren’t unusual for him.

A story in Wired today (Dec. 13) shows the tolls Musk’s single-minded obsession with building electric cars powered by clean-energy has exacted on his employees, and sometimes jeopardized his dreams as much as enabled them. Charles Duhigg interviewed dozens of current and former Tesla employees who described the chaos—and sense of purpose—Musk has brought to Tesla’s 40,000 or so workers. Duhigg portrays a company ruled as much by Musk’s inspiring vision of the future, as fear of his moods.

One young engineer, grilled by Musk about whether he was to blame for an assembly line malfunction, was reportedly fired on the spot when asking to clarify the problem. With Tesla’s financial situation growing more dire this year, Musk took to saying “I’ve got to fire someone today,” one executive recounted. “No, no, I just do. I’ve got to fire somebody.” One job candidate for a retail position was reportedly rejected because Musk disliked the color of their shoes (Tesla denies this). Managers kept skeptics out of meetings or avoided his desk to dodge Musk’s ire. Some came to work fearing every day would be their last at the company. As one former executive said, “Everyone in Tesla is in an abusive relationship with Elon.”

The routine grew so common it acquired a name: “We called it ‘the idiot bit,’” a senior engineering executive said. “If you said something wrong or made one mistake or rubbed him the wrong way, he would decide you’re an idiot and there was nothing that could change his mind.”

Tesla responded by email, saying production of the Model 3, its first mass-market car, was “excruciatingly difficult” for Tesla, but called Wired’s story an “overly-dramatic and sensationalized tale.” It denied suppressing internal debates or firing people without cause or disagreement with Musk. “That fundamentally does not make sense, as it would literally be impossible for Tesla to still be here if that’s how we operated,” a Tesla spokesperson wrote. “In order for Tesla to succeed, we must have extremely high standards and work harder and smarter than everyone else….Elon cares very deeply about the people with whom he works.”

Despite the departure of at least three dozen high-ranking employees within two years, more people have been willing to join Tesla’s workplace that is chaotic at best, or capricious at worst, because they say they feel they’re contributing to a bigger mission.

“It’s one of the few companies that is genuinely changing the world,” one former executive told Duhigg. “And everyone was so smart.” Musk’s seemingly impossible demands unlocked many people’s potential. “He’s someone who empowers you to be better than you think you can be,” said Todd Maron, Tesla’s former general counsel. “He has extraordinarily high standards, and so he pushes you to be your absolute best.”

But several employees argue Tesla was succeeding despite their CEO’s disruptions and self-inflicted wounds, not because of them. A former engineering executive argued Tesla’s feat was building the world’s most admired electric car while its CEO was having a public meltdown and executives were leaving the company. “That’s a real accomplishment,” said the executive. “That’s amazing.”

You can read the full feature here.