A good referee's best trait is being willing to make mistakes. I think as soon as a ref feels defensive on their calls and doubles down, it's over, and the game isn't being officiated well. Some other traits that improve the game is not having equalizing calls. Penalties are doled out strictly based on play - if you're trying to keep penalties even on both teams that's pretty dogshit and doesn't take each incident on its own. Any call should be based strictly on what happened, and not what the last call was, how many penalties that team has already had, or even on how that player has played earlier in the game. As soon as you let someone get away with something, you've lost. I'm happy that there's video replay and a command center to help refs call fairly, and even though it takes a minute to consult, it's worth it. Refs staying out of the way also helps. Ref ricochets are silly.