Listen, I'm not saying that my hatred is healthy. It actually borders on insanity for the most part, and I'm sort of okay with that. I think it's the "fanatic" part of being a fan. But to give it a bit of completely ridiculous clarity, it either stems for entire teams or certain players (and therefore their teams) like
@JJ Husker said. I grew up in CO, and when the Rockies left to become the Devils (so I hate the Devils to this day, plus my wife is a Ranger fan, so I have to), I was a sad little boy without a team. My best friend was from Chicago, so I ended up watching a ton of Hawks games and became a fan because I needed a team. Still to this day I'm a Hawks fan first, Avs fan second. So, I hate the Red Wings and Blues, initially because of the Hawks, but now also for the Avs.
Can't stand Vegas, they do their players dirty and their fans are obnoxious as hell.
Sorry
@admo, but as long as Evander Kane is an Oiler, hate them too.
F the Bruins because of Marchand.
Don't like any of the California teams, because, well, California.
Those are just a few examples. Welcome inside the terror that is my mind.