Deal with toxicity by being nice, if you always take the hits they will have nothing to use against you in the future.
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Deal with toxicity by shutting up, way too many times when I personally smurf silvers open their mouth with 'gg fb noob vayne' or something of that sort
that makes me blow off. I have the ammo that i'm diamond and they are bad and I decide to shoot it. Just be quiet because everyone has bad games.
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Deal with toxicity by not punishing them, but understanding them. Threatening to report just basically tells them 'ur fked n e ways just blow the building up m8.'
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Author's notes:
Even Riot does this sometimes, They'll issue a punishment out to a player without letting them know what they did wrong. Said toxic player makes the same mistakes because nobody is leading him the right direction.