Billie Eilish gets annoyed when her brother puts his dirty shoes near her face. An expert says there are pros and cons to working with siblings.

Billie Eilish and Finneas bicker over dirty shoes, but an expert says working siblings benefit from knowing each other's 'strengths, weaknesses, and quirks.'

• Finneas O'Connell and Billie Eilish talked about the challenges of working with a sibling on "Hot Ones Versus."
• Eilish described her brother's habit of putting his feet up while they worked on "Hit Me Hard and Soft."
• An executive coach shares the pros and cons of working with family.

Like most siblings, brother-sister duo Billie Eilish and Finneas O'Connell have had their fair share of tiffs. But something that has struck a nerve more than once for Eilish has been O'Connell's feet.

On Tuesday's "Hot Ones Versus" episode by First We Feast, the siblings had to choose between answering personal questions or eating spicy wings.

When Eilish asked what their biggest argument was while working on her album, "Hit Me Hard and Soft," O'Connell said, "I put my feet up on the desk a lot."

"He's a lot of times barefoot. He's a lot of times in very filthy shoes," Eilish said.

"This is the situation," she said, pushing the plate of wings away and plonking her feet on the table — snug in a pair of black Etnies shoes. "My face is like, right there," she said, pointing to the space beside her feet as O'Connell laughed.

The conversation took a more serious turn when O'Connell talked about an argument they'd had regarding honesty.

"To give you credit, I was very much like high and mighty about like, 'You're not being honest or authentic enough,' and you were coming up with such beautiful melodies and cool cadences," he said. "I learned a lot from being too egocentric in that process."

Released in May, "Hit Me Hard and Soft" is Eilish and O'Connell's third studio album together.

The siblings' partnership started in 2015 after O'Connell wrote "Ocean Eyes." The song was recorded when Eilish was 13, and she shot to stardom after uploading it to SoundCloud.

O'Connell, who also produces his music under the name FINNEAS, has shared about the success of his musical partnership with his sister.

"In the alternate reality where I wasn't involved at all, and I'd been like, just, sweating my way through, trying to have a music career for years? And then my sibling had one, and I wasn't involved at all? I think I'd be very tortured by it," Finneas told The Washington Post in 2020. "But the fact that we've had one in tandem makes a lot of sense."

How to mix family and business

Mixing family and business can be tricky, but Eilish and O'Connell aren't the only ones who have made it work.

Siblings Patrick and John Collison found success working together in the business world. After dropping out of college, they launched the payments company Stripe in 2010. The brothers are now both billionaires.

When asked what it was like working with family in an Ask Me Anything session by Stripe, Patrick said: "We spend most of our daily lives working and building things, creating, and why not do that with the people you're closest to? It's awesome."

Huda Katten, the founder and CEO of Huda Beauty, launched the cosmetics brand in Dubai in 2013 with the help of her sisters, Mona and Alya. Since then, Mona has branched out to create a fragrance arm, Kayali.

In an interview with Vogue Arabia in January, Huda reflected on their sibling partnership: "We're not in competition but as a family, we give each other feedback, because we want the others to succeed."

Marlo Lyons, a career and executive coach, told Business Insider about some of the benefits of working with family. "Siblings often have a deep level of trust built from years of growing up together. They know each other's strengths, weaknesses, and quirks," she said.

She also said that difficulties can arise from working closely with one another, such as inefficient decision-making or overstepping boundaries.

Her advice? "Recognize that you may be siblings, but that doesn't mean you know everything about each other. Be curious about behaviors or communication that doesn't make sense to you," Lyons said.

A representative for Eilish did not immediately respond to a request for comment sent outside regular business hours.