Cognitive Dissonance
This subject is likely way above my abilities to present it properly but it's been on my mind for quite a while and i've yet to see anyone bring it up to any degree... so here goes nothing:
There's a common variable that most people who hang around on these boards have in common and that they tend to forget is a thing because keyboards and screnns are distinctly impersonal:
YOU ARE ALL PEOPLE.
Every single person playing this game and roaming the boards is another human, regardless if it's a troll, a flamer, that 
player who refuses to stop 1v3ing despite the ammount of times it failed, a boards moderator, a person who praises riot's punishment system or one who does the complete opposite.
Most people forget that both themselves and the ones they are arguing with are the same beings with the same perception of reality: self centered. I don't mean narcissistic or ego centric. I mean that the both of you have the same view point with respect to each other, you both think that the other is in the wrong and that you are in the right and you choose to handle that disagreement in your own way.
- Some do it by trolling or afking or inting
If you are someone who does that, you are playing against their own interests just to punish the other person on a short term basis while ignoring long term consequences.** You're losing your own game** that you joined for the purposes of grabbing a win just to "teach a lesson" to the stranger you just met and will likely never see again after the end game screen is closed!
Just take a moment to understand how blatantly absurd that is!
- Some do it by flaming It's been 9 seasons for me. I've yet to understand the logic of "flaming to "defend" yourself from flame". So many people who bring up the "i was defending myself when i was flaming back" argument back it up by comparing it with real life violence and our natural flight or fight response to it.
THIS IS NOT REAL LIFE. you are not in any form of danger. the only thing that is in danger is your ego, which you can protect by muting. You didn't know the person flaming you existed up to this game so why do you care what they have to say?
This is a game with a chatbox. a chatbox that i've come to mostly ignore unless it starts getting too spammy with meaningless drama, at which point i procede to ignore it further while taking notes of slurs for the end game screen's report stage. I've never muted anything. Neither pings, nor emotes nor other players. But that's me. That's my way of dealing with flame.
But let's talk about the toxic way: someone plays less than ideal, fails at a play they were trying to make or starts flaming you first for whatever reason. Why are you flaming too?
Try to look at the situation from the other person's point of view: you failed at a play, played less than ideal or expressed frustration in verbal fashion and someone else decides to respond to the above examples of things not going well with toxic behaviour.
what does that do for you?
have you EVER reacted to another player adressing you in a negative way by admitting you are in the wrong? if not then what makes you think that you doing that to someone else will have that effect in particular instead of turning a team based game (with simple objectives that requires minimal to no chat interraction) into a shouting match that doesn't help with the winning part?
(and even if you did or would react in that manner, not everyone is like you. the most probable reaction is not yours so don't expect it from anyone!)
YOU ARE BOTH PEOPLE
As such, you are both prone to making mistakes,(some more frequently than others)
Why are you antagonising someone else for not being Faker even tho you, yourself, are not Faker either?
I understand venting but you don't need to pour salt on a fresh wound to vent frustration. All you're doing is turning a regret into anger for no other reason than to be a jerk. If you want to vent, do it by winning the game. Avenge your teammate who died to a more skilled opponent by killing an enemy of your own!
When your teammate failed, he knows it himself! There's no need for you to readress something that is overwhelmingly obvious to both of you! There's no need to be a jerk! Instead pick up the pieces and try to help him to not fail again. And again. And again. As many times as it takes! Even if he never actually succedes and the game ends in a loss, you made someone's day better by not kicking him when he's down. I'd wager you'd apreciate that if it happened to you, right?
When you fail and someone else decides that the best way to adress the situation is to put you down,** let him**! ignore him! Mute both chat and pings if you have to! Just try to do better next time! And the time after that. If you end up losing, Learn from the experience and try to do better next game!
- Some even do it by banning prepicks If you ever do this for any reason then you are part of the problem! More often than not, when this happens, the person you banned the champion from gets either trollish or toxic or both. The few people who don't care are not worth the gamble. Don't be selfish and let people play wahtever they want! looking up their mastery level on that champion means nothing and neither does their account level.
The 
with the highest mastery level on the planet is 8.6 million mastery points strong on the champion and despite being level 420 is Bronze 4.
Matery points aren't everything.
Win rate in previous games is irrelevant to the current game.
Stop being toxic for stupid reasons and let people play what they want to play!
Regardless of what conterproductive path you decide to take when you discover that your team is not the "dream team" you would have preffered, unless a punishment happens to either of you due to the above choices, neither of you is likely to remember the other one exists when the next game begins just as you didn't realise each other exists before the game started.
The only thing being actually damaged is your (and your temporary group of players's) account's elo rating and your account's toxicity status. If your objective is not to win the game at any cost and instead have a slapping match with randoms just because they disagree with your personal perception of reality then why are you playing league instead of hanging out on reddit or twitter???
[zombie-nunu-bummed]
I hope i managed to get my point across.
