You hear a lot of advice about building trust with your team, being transparent, and treating coworkers like family. It’s good advice in principle, but it’s also incomplete. The uncomfortable truth is that most coworkers aren’t your friends, and treating them as if they are puts you at risk. Understanding where to draw boundaries around trust can save your career.

Your Coworkers Have Different Incentives Than You

At the core, coworkers want things you want: promotions, recognition, good projects. Sometimes your interests align, sometimes they don’t. Your coworker doesn’t have the same stake in your success that you do. They might be friendly, but when it comes down to a choice between your promotion and theirs, their interest wins. This isn’t malicious; it’s just human nature and incentive structures. The problem arises when you treat coworkers as though they do have the same stake in your success. You can be warm and professional without assuming their interests are aligned with yours.

Information Shared in Confidence Often Isn’t Kept Confidential

You confide in a coworker about a problem you’re having, or some personal information, or even just frustration about a project direction. Weeks later, that information has made it back to you through the grapevine, often with embellishment. Even well-meaning people share information; it’s how humans bond. The lesson: be cautious about what you disclose at work. This doesn’t mean being robotic or completely closed off. It means being intentional. Share enough to be relatable and human, but not so much that you’re putting ammunition in the hands of people who might use it against you. Keep vulnerable information for people outside work or one or two truly trusted mentors inside work.

Friendly Doesn’t Mean Trustworthy for High-Stakes Decisions

You can have a great relationship with a coworker and still not trust them with sensitive decisions. Just because someone is fun at happy hour doesn’t mean they’ll advocate for you in a promotion meeting, or keep confidential information about a family problem, or refrain from one-upping your story at a larger meeting. Separate the dimension of social connection from the dimension of trustworthiness for serious matters. You can enjoy someone’s company and still maintain professional boundaries around what you actually confide in them.

Trust Is Specific, Not Global

You might trust a coworker to handle a technical problem but not trust them to keep a secret. You might trust them to collaborate on a project but not trust them to advocate for you with leadership. Don’t make the mistake of extending trust in one domain to all domains. Someone can be reliable and competent in their work while still being someone who gossips or who’s more self-interested than you’d like. Calibrate trust to the specific domain and the specific stakes.

The Best Working Relationships Are Built on Clarity, Not Intimacy

The coworker relationships that last and work best aren’t necessarily the most intimate ones. They’re the ones where expectations are clear, communication is direct, and both parties are transparent about what they need. You can have a close working relationship based on professional respect and mutual benefit without being friends or confiding deeply. These relationships are more stable because they’re not dependent on personal chemistry in the way friendships are. If you focus on clarity and directness instead of trying to deepen intimacy, you get better working relationships.

Build Your Support System Outside Work

The deeper your emotional support system is outside work, the less you need from coworkers, and the fewer mistakes you make around trust. You have people outside work you can vent to, confide in, and get advice from. You don’t need to look for that from colleagues. This actually makes your professional relationships better because you’re not trying to meet needs at work that should be met elsewhere. You can show up as a professional version of yourself instead of trying to make coworkers serve as friends or therapists.

Trust is important at work, but it’s more important to be clear about what you’re trusting and whom you’re trusting it to. The people who protect their careers effectively aren’t cynical; they’re realistic.