This is Ranked

It's particularly bad in League because of the team-based nature of the game as a noise factor coupled with its relative complexity. One of the most frustrating things is that you can, for example, make a serious error being too aggressive or insufficiently aggressive that at least partially depends on the relative aggression of your teammates.

If your team engages and you don't because you think you'll just add a death, but you could have aced them rather than lose that teamfight...that's a game changing mistake.

If you engage or commit to someone else's bad engage and the result is that your team gets wiped while out of position and gives up mid inhibitor...that's also a game changing mistake.

Now, have fun when 5 people have different opinions on which one is the mistake, and of course there's grey area here because if an otherwise good engage becomes a bad one because a bad player won't commit...it's still a misplay to engage knowing that teammate won't when given the choice.

And this is just one example. This effect is particularly nasty in league and is a contributing factor to some of the toxic communication you see. Far from the only factor, but a significant one all the same. Probably the worst part is that a bad player can assess another person on the team to be playing poorly and be correct, without realizing the he himself is also playing poorly and that these feed off each other.

The first step to becoming better is to accept that you are trash, once you let go of the self-centered ego-based illusion of superiority you become free to learn from your mistakes and grow. The second step is to stop perpetuating the behavioral stereotypes we accept as the "norm" upon others.

In short, humility will set you free, and raise your Elo.