It is human nature to make mistakes in everyday life, but this is one mistake that is a very costly and clearly changed the momentum of the game.
Early in the third period against the San Jose Sharks, the Anaheim Ducks had a shot that was initially covered by Antti Niemi, but the puck happened to trickle past the Sharks goaltender. The whistle was blown by the referee and the play was under review. After reviewing the play with the situation room in Toronto, the referee called it a no-goal. According to the NHL, rules this is the rule in question:
According to Rule 78.5 (XII), Apparent goals shall be disallowed by the referee when the referee deems the play has been stopped, even if he had not physically had the opportunity to stop the play by blowing his whistle.
In my opinion, this has to be by far the most ridiculous ruling in hockey. If you watch and hear the replay, you can clearly see the puck crossing the line before a whistle is heard. This further proves that the situation room in Toronto needs to do a better job at looking and hearing closely in games.
Because with how the game between the Ducks and Sharks was going, the game could be a lot closer than the score showed. With Patrick Maroon scoring later on in the third period, this would probably be a 3-2 Sharks lead, which would be a very interesting turn of events. The no-goal turned away any possible momentum that the Ducks could have gathered that would have given them a fighting chance to come back and win.