Within one of the great sports books, certainly the finest on hockey, read these passages:
NHL refereeing is an impressionistic exercise … Mostly, it is the extent of a referee’s discretion that makes hockey so difficult to officiate. In hockey, officiating is like doing spot-checks on New Year’ Eve. Anything signaled is bound to be an infraction, and so good calls can seem like bad ones, everything becomes arguable, and no one is happy … It’s not what is a penalty, it’s what the game allows. And the more it allows, the more it gets, and the more it gets, the more it allows … Hockey is the most difficult of professional sports to officiate well.