Hello and greetings summoners.
Everyone of us has already met toxic players or trolls in league of legends. Some of them might cross the lines toward you and such.. in a way that you wanna mute them and report them.
Since I started league I didn't knew how to deal with this kind of toxcitiy. But I have learned to control my anger, think to myself that I was like him before but I have changed now, just PITY the poor thing.. ignore his hateful messages..
Sometimes when I feel someone wanna start a fight or flame I would simply ask him : "Why so toxic?"
most of the time it works because it gives them an indirect hint or reminder that they would get reported if they keep going on this negative behaviour (without the need of typing reported)
it really works and makes them shut up during the rest of the match.
PS: I already asked a rioter support if it is OK to point to someone that they are toxic in game and they said it is OK as long as you put it in a nice way without being harsh or mean to them.