That’s partly because the top benefits of coming into work are what they’ve always been, finds the latest report from WFH Research: personal interactions that are hard to replicate, mainly collaboration, instruction, and socializing. (On the other side of the coin, remote work means saved time and money, and peace and quiet.)

As the data breaks down, workers who go into the office spend 25% more time on career development than their remote counterparts do. In-office workers also spend significantly more time per week—about 40 minutes—getting mentored or mentoring a colleague. And they log about 15 more minutes per week carrying out professional development and learning activities. The data comes from a survey of 2,400 U.S. adults whose jobs allow at least some days of remote work. That group convenes each month for WFH Research’s Survey of Working Arrangements and Attitudes. 

“Bottom line, personal interactions among colleagues diminish by a significant amount when someone works from home,” write the authors behind the research, Nick Bloom and Jose Maria Barrero. “That is a cost workers and firms pay in terms of slower on-the-job learning, in exchange for the flexibility and personal autonomy gained when working from home.” 

Workers are well aware of the tradeoffs. Most feel remote work helps them balance their job and personal lives, making them more driven and productive when they’re on the clock, a recent study from Pew Research Center finds. That’s doubly true for women, caregivers, parents, and workers from underrepresented groups, who all consistently prefer flexible arrangements. However, many also felt that working from home hurt their chances for mentoring and connecting with colleagues.

It’s harder to connect with colleagues and build relationships with senior leaders, many workers expressed in a Glassdoor survey from last year. And many—mostly Gen Z workers—said they feel their working arrangement has actually stunted their progress. That’s probably because Gen Z, who are early on in their careers, stand to benefit the most from mentorship.

When colleagues form strong relationships with one another, they’re more likely “to innovate and share ideas, get more work done in less time, and generally enjoy their job more,” Jill Cotton, a career trends expert at Glassdoor, told Fortune. “Engaged employees will stand out to their boss, increasing their opportunity to be identified for career growth within a company.”

The lopsided mentorship picture lends credence to pro-office arguments, which are most often found among seasoned bosses like JPMorgan Chase CEO Jamie Dimon, venture capitalist Marc Andreessen, and Twitter CEO Elon Musk. Jefferies CEO Rich Handler has previously said that workers should stay remote if they just want a job, with short-term goals and a paycheck. But he said if they want to build a career, focused on long-term goals and personal development, they should go to the office.

While he thinks that hybrid work will stick around, he told Fortune that workers shouldn’t dismiss the value of the office. “The reality is, if you are in the office, you get pulled into a lot of interesting ‘real time’ situations because physical presence matters,” Handler said.

But that’s not to beat down the increased productivity many workers say they experience while working from home. All things considered, it’s no wonder hybrid work seems to be the best of both worlds; even the experts behind WFH Research encourage it. By working to ensure teams are in the office on the same day or two per week—and online the same hours when they’re home—managers have the best shot of making everyone happy. It’s what Bloom calls an organized hybrid model, in which in-office days are dedicated to collaboration, and work-from-home days prioritize deep, quiet work. “In 2023, we’ll be laughing at anyone who does anything else but hybrid,” he told Fortune last year.

In a fully remote work environment, workers might be saving time and cash on their commute. But there are some things money and an extra hour of sleep can’t buy.