I've raege-quit myself a couple of online communities. The atmosphere has just been on it for me personally so toxic and unhealthy that I've had to quit for my sanity's sake.
Oh yeah, I've rage quit from a lot of games. Some games are just super toxic and you can't help but to feed off of the toxicity. League of Legends is by far one of those games. I've also rage quit from other games but most of those are due to quick games and the game was so one sided it's logically better to speed up the process for both people and quit.