Rage-quitting is such a serious issue in this game.
The main skill you need in a MOBA is the ability to adjust and certain players REFUSE to do this.
They won't focus vision/positioning, they won't focus map awareness or objective/CD timers, etc. etc.
You over-extend with no wards up and get ganked and instead of accepting that and adjusting, you just flame your team and rage-quit?
It's the single most annoying thing in the game for me. It flat-out ruins games and makes it hard to want to queue again.
I report this every single time, but most players don't just randomly rage-quit. It's a habit for these players. You would like to think after a few offenses, that player would just be banned from the game.
But do we really think/know it's happening though?