Flaming
I don't know how many times I have said it but flaming doesn't do anything. It hurts more then helps, Riot literally has a fact that says that "Players who flame lose 13% more games How much simpler can it get. I don't care if you think those things what matters is what you type in chat. It also doesn't help to backtalk. If someone starts flaming you, don't start flaming them back. Simply mute them, that is all it takes.