BY ALL ACCOUNTS, Facebook had a bad 2017. Younger people are increasingly choosing Snapchat and Instagram over the social media giant, and regulators are closing in on several fronts. Then right at the end of the year, a number of former executives including ex-president Sean Parker revealed that the site exploited “a vulnerability in human psychology”. Chamath Palihapitiya, the former vice-president of user growth, expressed regret for his part in building tools that destroy “the social fabric of how society works”. In spite of this, Facebook has been named the best place to work by Glassdoor––for the third year running.

It’s easy to put this down to the company’s now-famous perks, including free meals, “baby cash” for new parents, an on-site hairdresser, health centre, dental surgery and dry cleaning. But any HR professional worthy of the name will tell you that’s not why its employees are excited to go into work every day. When it comes to workplace satisfaction, Facebook reigns supreme because of its culture.

It would be careless to say that was the only reason. Of course, Facebook is hugely popular and a true original. You could say it is an era-defining company. But regardless, culture is the main reason for its reputation as a great place to work. According to Janelle Gale, the Vice President of Human Resources at Facebook, employees are told from their first day at Facebook that they should “own and contribute” to the culture. This immediately makes new employees feel at ease and at home, and both involved and invested in the company.

But this doesn’t mean that Facebook’s culture is weak or easily changeable. The opposite, in fact: because that same culture is underpinned by a strong value system that revolves around transparency, social value, speed, boldness and impact, its most important pillars stay standing while everything else flexes and adapts to changes in personnel, new trends or emerging needs. Facebook looks for these five qualities in all its potential employees so that new recruits both strengthen the existing culture and add some of their own uniqueness to it.

It can be hard to account for culture on a balance sheet. We know it’s there, but we can’t measure it. That’s why historically, it has been neglected at businesses all over the world. But culture is the defining characteristic that creates value at a company. It’s the reason why Facebook, as well as Apple and Google, are valued so highly: the product may be successful, and profits may be high, but the culture means that they can navigate an increasingly fast-changing landscape and create opportunities out of an unknown future.

In its true role, any organisation’s HR department is the custodian and defender of the culture. HR professionals understand that as the rate of change in the world accelerates, and volatility increases, a company that is intellectually and strategically agile will flourish and grow, and that has a lot to do with culture. What Facebook and other organisations have shown is that if you get culture right, profits don’t just go up, but employee satisfaction goes up as well.