That testimony may read like an anonymous Blind post from a disgruntled, strung-out worker laboring under the bombastic CEO Elon Musk at Tesla, X (formerly Twitter), or SpaceX. But it actually came from billionaire Microsoft founder Bill Gates. 

Every manager has a different leadership style, he said during a fireside chat this week at the Economic Club of New York, which had just honored him with the Peter G. Peterson Leadership Excellence Award. “Elon pushes hard, maybe too much,” Gates said, first reported by Business Insider. Even the late Steve Jobs—the genius and notoriously thankless manager who co-founded Apple—in Gates’ opinion, did the same.

As for Gates himself? “I think of myself as very nice compared to those guys,” he said, though he admitted to some micromanaging tendencies of his own. 

Naturally, there’s more to the story. In order to lead a supremely innovative company—like Musk’s Tesla, Jobs’ Apple, and, yes, Gates’ former Microsoft—Gates acknowledged that “hardcore” leadership is often necessary. That’s where he sets himself apart from Musk, about whom he has often expressed public disapproval.

At the fireside, Gates said he tempers his own leadership instincts by viewing everything through “an innovation lens,” but admits that wasn’t always his approach.

Indeed, Gates’ leadership in the early Microsoft days was defined by a short fuse. According to a 1993 biography, Gates often sent “critical and sarcastic” midnight emails to workers, including one in which he harangued a programmer for submitting “the stupidest piece of code ever written.” 

Employees at the time called the Gates-led Microsoft “confrontational,” “demanding,” and “intense.” Gates has softened over time, and is now known for a leadership style that embraces feedback and employee input. 

Musk seems not to have learned Gates’ lessons, and remains avowedly more focused on cultivating a cutthroat culture. Last year, days after buying the company, Musk infamously sent a 2 a.m. email to the entire Twitter employee base instructing them to be “extremely hardcore” and to work “long hours at high intensity.” At Musk-run Twitter—pre-X—he added, “only exceptional performance will constitute a passing grade.” That’s not just lip service; Musk himself is a notoriously hard worker who has been known to sleep at Tesla’s factories. 

Ad hominem attacks

Of course, Gates might have some beef. Microsoft and Apple are notorious competitors, and he and Musk have exchanged words in the past. While Gates may not agree with Musk’s leadership style, Musk has been decidedly more open about his distaste for Gates as a person. 

Following a business slight—Gates shorting his Tesla stock—Musk was “super mean,” Gates told Musk biograhper Walter Isaacson. Musk, on the other hand, appears to have little concern about issuing ad hominem attacks. He has loudly insulted Gates’ intelligence and even denigrated his appearance. Last year, he tweeted a photo of Gates with a side-by-side of a pregnant emoji.

Plus, per Isaacson, Musk reportedly took Gates’ lack of support for Tesla as a betrayal of his values. “How can someone say they are passionate about fighting climate change and then do something that reduces the overall investment in the company doing the most?” Musk reportedly wondered aloud. 

He refused to work with Gates from there on—even on charitable initiatives. “At this point, I am convinced that [Gates] is categorically insane (and an asshole to the core),” Musk told Isaacson. “I did actually want to like him (sigh).”

They also disagree on one of Musk’s prime ambitions: Life on Mars. “I’m not a Mars person,” Gates told Musk’s biographer. “He’s overboard on Mars.” 

But Gates’ gripe that Musk (and Jobs) pushed “too hard” is valid if you consult research. Giving workers the space and confidence to do their best work—where, when, and how it appeals to them—is the best way to ensure enduring efficiency. Insane amounts of pressure tend to only worsen morale and performance—a recent Slack survey of 10,000 workers finds that workers who feel obliged to work late report 20% lower productivity during the day. And toxic, abusive bosses end up sending their most ambitious workers right out the door first, finds a group of researchers from the Stevens Institute of Technology and University of Illinois Chicago. 

That might make Gates the better boss. So much for “hardcore.”