There's such a thing as good sportsmanship, but there are a lot of players that don't play by these rules. And when it comes to the fans - they've got the leeway to throw all common courtesy out the window (and the copious amount of alcohol doesn't help) without it affecting their careers.
Still, there are certain things you'd expect fans to avoid - like taunting a clearly injured player. During a 2001 game in Colorado, hockey player Steve Sullivan, of the Chicago Blackhawks at that point, was hit in the face during a game. When he came face-to-face with one particular fan, he got anything but sympathy.
"I was slowly going to the bench with my trainer, and a fan who was sitting behind the glass started to heckle me and just started calling me some names, that I really can't say on TV," Sullivan later recounted in an interview with TSN. "I just thought when a player is hurt you just, common courtesy, just be quiet."
Yet while this obnoxious fan looked to go unpunished - karma had other ideas. In what has become a cult favourite on YouTube, a later strike left sent the puck flying over the glass, at the precise angle needed to strike the same fan in the face:
"And luck be it that the puck got behind the net and threw it over the glass, and it clipped the same fan right in the forehead and he started bleeding probably worse than I was," the NHL player continued. "I took it upon myself to go back and give him a few words of my own, and I think his girlfriend found it pretty funny also."
Honestly, is there a better example of karma out there? You've got to think that hockey fan had to rethink how he acts in games in the future.
