Ask most golfers what makes a green fast and true, and you'll get a shrug — it just is, or it isn't. Ask the people who mow it, and you'll get a much more specific answer: it comes down to how sharp the reel is, how precisely it's set, and whether the roller underneath is grooved or solid.
Per the USGA Green Section Record's own reporting on the craft, a sharp, correctly adjusted mower cuts grass cleanly instead of tearing it — the difference between a green that heals and one that stresses out under its own maintenance. Even the choice of roller matters: solid rollers sit higher on soft turf than grooved ones, which is why crews switch to them the moment the perimeter turf starts showing wear.
None of that shows up on a scorecard. It shows up in every putt that rolls true instead of wobbling off-line two feet from the hole — and in the hours someone spent, before sunrise, making sure it would.
Source: USGA Green Section Record