Donald Trump’s staff have privately grumbled about the new house guest at Mar-a-Lago who won’t seem to leave, while the company in question, Elon Musk, continues to step out ahead of Trump on matters of both policy and personnel.

But even as some Trump allies are stunned the new friendship has continued — and even as Musk’s influence proves to have real limitations — the incoming president still can’t seem to get enough of it.

Trump’s field trip with Musk on Tuesday to marvel at the billionaire’s SpaceX launch in Texas was just the latest display.

Trump brought an entourage of aides and lawmakers, including Sen. Bill Hagerty (R-Tenn.), a top contender for Treasury secretary, to the launch. The president-elect was warmly greeted with a hug from Musk and a show-and-tell of his space base.

The incoming president and the world’s richest man have remained seemingly inseparable over the last two weeks as Musk has sat in on calls with world leaders, joined Trump and his family members for meals, and was ever present as the president-elect charts out his second administration.

Still, there are indications that Musk’s influence on Trump’s decision-making process extends only so far. Musk has publicly advocated for both personnel and Senate leadership picks that didn’t materialize, while straying from the established talking points of Trump and his staff.

Among Musk’s defeats: Pushing for Sen. Rick Scott for majority leader (it went to Sen. John Thune, after Trump declined to get involved); and touting Howard Lutnick for Treasury secretary, only to watch Trump appoint his transition head to lead the Commerce Department instead. Musk was especially vocal about Lutnick, announcing his support in a post on X to his millions of followers. Trump was apparently unmoved, as Lutnick ended up with an administration job different than what he lobbied for.

At the same time, Trump’s selection of Brendan Carr as Federal Communications Commission chair this week had Musk’s fingerprints on it. Carr’s advocacy has lined up closely with Musk’s interests throughout 2024, and the two have amplified each other on social media. He’s now poised to shape key parts of Trump administration policy — and in ways that stand to benefit Musk’s businesses, like the satellite broadband service Starlink, which could be in line for more subsidies and contracts.

The push-and-pull is all part of what’s shaping up as perhaps the most important friendship in America. Trump is clearly enamored: He has called Musk a “genius” while listening to ideas and suggestions shared by the quirky Tesla and SpaceX owner. And Musk, who dubbed himself Trump’s “first buddy,” has been particularly captivated by the process of standing up a new White House. He has approached the transition process like a scientist, according to a person close to the former president, picking apart problems and carefully observing as MAGA scenes unfold, like his first UFC fight last weekend.

In the process, he has won over not only Trump but some of his top allies. On the flight to the UFC match, Musk spoke at length with Donald Trump Jr. and other guests about his different ideas.

“I got off the plane, and I was like, I wish we were going 20 times further,” Trump Jr. gushed to Charlie Kirk. “I wish we were there for 20 hours because it was one of the most fascinating conversations I’ve ever had. The level of genius — you can’t even comprehend it. You throw out questions, and I just want to listen.”

But while aides and advisers have complained to the press that Musk is still around and butting into transition decisions, Trump and his family haven’t appeared to care.

So far, Trump, who enjoys surrounding himself with an eclectic array of celebrities and business titans at his club, has tolerated behavior from Musk that might have grated him with others.

“Elon Musk and President Trump are great friends and brilliant leaders working together to Make America Great Again. Elon Musk is a once in a generation businessman and our federal bureaucracy will certainly benefit from his ideas and efficiency,” said Karoline Leavitt, Trump-Vance transition spokesperson.

In the last week alone, Musk and Trump have met up in Texas — where a Tesla Cybertruck joined Trump’s motorcade — traveled together to Washington, D.C., to address GOP lawmakers, chowed down on McDonald’s in the early hours of the morning, attended a professional fight and sang together in front of all of Trump’s friends at Mar-a-Lago. On election night, Musk and his young son, named X, joined the Trump family photo at the urging of Trump, and Trump’s granddaughter in the days after said that Musk had achieved “uncle status.”

The former president has even joked that he doesn’t know when Musk is going to leave.

“Elon, like President Trump, doesn’t give a shit about what people think about him, and President Trump finds that refreshing,” said a person who has watched him and Musk interact recently. “Elon is probably the only other man in the world who can truly relate to President Trump.”

The friendship appears especially satisfying for Musk, who is in the room for startup-style discussions unlike any he has been part of before.

“There aren’t any larger problems than being the President of the United States. And so I think he’s fascinated with solving problems, and this gives him a front row seat in helping solve problems that you otherwise would never be faced with,” said the person close to Trump.

Though Musk has lost out on some Trump decisions since the election, it’s not as if he’s been without pull. The president-elect’s visit to the SpaceX launch alone is attention most CEOs could only wish for.

Musk last week also was given the newly created title of co-leader of the Department of Government Efficiency, or DOGE, a reference to the cryptocurrency Dogecoin that Musk had previously touted.

In prime 2024 fashion, the story of Trump’s new cost-cutting initiative goes back to Musk’s riff on a podcast a few months ago.

“I have discussed with Trump the idea of a government efficiency commission,” Musk told host Lex Fridman during an August interview. Musk then brought it up with Trump himself during an Aug. 13 conversation on Musk’s social media platform X. Trump responded warmly, calling Musk a “great cutter.”

On Sept. 5 Trump announced that he’d establish the commission, and after his win this month declared the establishment of DOGE.

Musk also influenced Trump on the merits of this novel satellite broadband service. On the campaign trail this fall, Trump said he initially knew little of its operations (“What’s Starlink?” he asked). But when he saw how the satellite service could help during hurricane recovery efforts — and amid talks about the offering with Musk — he marveled over its promise. He recounted satisfied Starlink users who told him the service was “much better than the wires.”

That could lead to tangible benefits for Musk, as Trump agency leaders weigh various technology options to connect more Americans to broadband.

Allies and critics are paying close attention to where the friendship goes from here, given the massive implications.

“It’s a bromance,” said one Mar-a-Lago member who has witnessed Trump and Musk’s interactions, “and they are having a blast.”

Derek Robertson and John Hendel contributed to this report.