It’s very difficult to score a goal in the game of hockey. Players have to navigate across the ice at breakneck speed, without losing control of the hockey puck (or their own balance), and—with perfect timing—slide the puck past the goalie and into the goal. This is one reason why hockey actually allows games to end in a tie. Players (and spectators) could go for an hour without seeing a single hockey goal; rather than risk extending the game indefinitely waiting for the tie to break, the teams simply call it “quits.”
Considering the odds, many players are very happy if they are able to score a goal even once in a game. Imagine their amazement if they are able to score three (note: this doesn’t include “assists,” where they simply passed the puck to the scorer). This rare accomplishment is called the “hat trick.”
When a player achieves a hat trick, the fans in the audience throw their hats in the air (often cheering and shouting in appreciation, too). This is their way of acknowledging the difficulty of the accomplishment and saying, well, “Hats off to you!”
Hat tricks are so incredibly rare that professionals can go through their entire career without achieving them. It is interesting to note, however, that Wayne Gretzky—a Hockey God and member of the National Hockey League hall of fame—was able to score hat tricks not once, not twice, but fifty times in his 20-year career (1979 to 1999).