Most teams try to go fast by hiring the fastest people. The best teams go fast by building trust, which is slow. That's what the old military saying really means: slow is smooth, smooth is fast.
The line is usually credited to the Navy SEALs, but its paper trail is murkier. A 1978 school yearbook describes a German teacher who raced her Porsche as a hobby, and whose "basic philosophy of racing is 'smooth is fast.'" The 2000 edition of the Army's Ranger Handbook says: "Move in a careful hurry. Smooth is fast and fast is smooth. Never move faster than you can accurately engage targets." A 2001 Marine Corps manual on urban combat puts it more bluntly: "You cannot rush." A line later it spells out the saying itself. Whoever said it first, the point is the same. Speed you can't control isn't speed.
Simon Sinek tells a story that shows what this means for people rather than footsteps. He says he asked the Navy SEALs how they choose who gets onto their most elite team, and they drew him a chart with two axes. One was performance: how good you are at your job. The other was trust: what kind of person you are off the battlefield. As the SEALs put it to him, "I may trust you with my life," but would I trust you with my money, or with my wife?
Everyone wants the high performer with high trust. Nobody wants the low performer with low trust. The interesting part is the other two boxes. In Sinek's telling, the high performer with low trust is "a toxic team member," and the SEALs would rather have "a medium performer of high trust, sometimes even a low performer of high trust."
It's worth being honest about what that is. Sinek has told the story in many talks, and he credits the idea to Rich Diviney, a retired SEAL officer who ran training for a specialized command and has worked with him since. It's an account of a conversation, not a study. The research on teams doesn't test that exact choice, but it points in a similar direction.
In 2015 Google published what it had learned from studying more than 180 of its own teams over two years, a project it code-named Aristotle. The conclusion was blunt: "Who is on a team matters less than how the team members interact, structure their work, and view their contributions." The single most important factor was psychological safety, which Google described as whether team members can take risks without feeling insecure or embarrassed.
Amy Edmondson at Harvard introduced the idea of team psychological safety in 1999, building on earlier work on organizational change, and defined it as "a shared belief that the team is safe for interpersonal risk taking." In a study of 51 teams at a manufacturing company, she found it was associated with learning behavior, and that learning behavior in turn linked it to team performance. Earlier, studying medication errors in two hospitals, she found differences not just in how often errors happened, but in how likely they were to be detected and learned from. And a 2016 meta-analysis of 112 studies, covering 7,763 teams, found that trust within a team is positively related to how well it performs.
Here's why that's the same lesson as the saying. A brilliant teammate you can't trust makes everyone around them slower. You double-check their work. You keep things from them. You hide your own mistakes in case they use them. Every one of those is friction, and friction is what turns fast into jerky. A team that trusts each other doesn't have that drag. Mistakes get said out loud, fixed and learned from, so the team moves smoothly, and smooth is fast.
The catch is that trust is slow to build. Sinek describes what makes it possible as a circle of safety: when people feel safe among their own, he says, the natural reaction is trust and cooperation. In his 2014 TED talk he tells a story of Marines in the field where "the officer ate last, and he let his men eat first." Nobody earns that kind of loyalty in a week. It's built in small moments, over and over, mostly when nobody important is watching.
I saw a version of this in Special Forces selection in Cyprus, which is run in pairs: you get each other through or neither of you passes. In a pair like that, the partner you want isn't the fastest one. It's the one you can count on when it gets bad.
So if you're building a team, choose trust first and build it on purpose, even when that feels slow. Fewer stars. More people who tell each other the truth. It will feel like you're going slowly. That's the point. Slow is smooth, and smooth is fast.