@WAZAAAAA I too not very understand until recently (google not translate very well) Know it when I play a 4vs4 game, example: When the game just started, without a clear reason, someone suddenly quit the game, so everybody cant enjoy playing game.
Or he did not quit... but he either idle, or he begin attacking his own teammate, so the other 3 begin quitting.
They call him "an exploiter." This just only couple example...