Elon Musk had quite the weekend, following a week in which his “kid-size submarine” was shunned as a means of retrieving a dozen Thai boys stuck in a flooded cave. The Tesla CEO was clearly stung by the opinion of the rescue team that his metal tube was of little use in the circumstances, and he simply would not let the matter lie.

After Vern Unsworth, a British diver who was involved in the rescue, derided Musk’s offer as nothing more than a public relations stunt—telling him he could “stick his submarine where it hurts”—Musk lost it. He tweeted that it was suspect for a British man to be living in Thailand, said Unsworth was a pedophile, and even doubled down in a subsequent tweet, saying: “Bet ya a signed dollar it’s true.”

Unsworth, understandably, is considering legal action over the attack. Musk has deleted the offending tweets, but the exchange left him looking nasty and more than a little self-serving.

How did it get to this point? At least part of the issue has to be the hero worship that surrounds Musk, much as it once surrounded Steve Jobs.

To the point of practically being a walking meme, Musk is the enthusiastic avatar for a Silicon Valley culture that says anything is possible with enough bravado thrown at it. He has had multiple songs of praise written about him, with a sample lyric reading: “Elon, one to lead us all / The champion for the future of humanity.” Even if it’s leavened with a pinch of irony, it’s not hard to see how such deification can go to a person’s head—especially when the person in question continues to make genuinely impressive achievements in his field.

Even when backed up on Twitter by an army of fans who lash out at his critics, no-one should be so arrogant as to believe that expertise in their field gives them more insight into other fields than those who are on the ground—or, rather, in the cave. Even if his original intentions went beyond self-promotion, it was foolish of Musk to insult a hero (and an expert in his own domain) for pointing out the unsuitability of Musk’s cylinder. Those who lack humility risk humiliating themselves.

A version of this story first appeared in CEO Daily, Fortune’s daily newsletter on succeeding big in business. Subscribe here.