It is said too many times that the good umpires are the ones which go unnoticed.
I wholeheartedly disagree. A horrid umpire can go unnoticed just as well or better because they don't have the guts to make a difficult/unpopular yet correct call. A good umpire is going to make that call regardless of the consequences, because it is the right thing to do. A good umpire can not be timid in the least bit when it comes to asserting himself into the game when needed, and will know when and how to insert themselves into the game.