Basically any competitive e-sport. Back when I played CS:GO, matchmaking was like flipping a coin where heads gave you a decent team and tails gave you one person with no microphone and McDonalds wifi connection, two 13 year olds who gang up on you to trashtalk you the entire game while simultaneously bitching about everything that happens, and one guy who decides to argue with them the entire fucking time. League of Legends? 500 times worse. If you're going to play online games, find some friends or make it a point to friend request all the cool people you meet because they're few and far between the squeekers, trolls, and absolute sociopaths.