I coached several years of my son’s football & basketball games. I never was a ref. I did however learn to be friendly with refs and I almost always felt I got a fair deal. Of course, I always figured elementary and middle school refs are about as good as elementary and middle school players! That keeps your perspective as a coach!
With NFL refs, my take is they know they are being watched on every play by millions of people, dozens of cameras & almost every call is instantly reviewable. They also know they are being watched by their spouses, kids, friends, etc. No one wants to screw up in front of everybody they know & love. I usually get upset at ref calls multiple times every game, but I keep myself from fixating on them because of my previous points.