Respect the Skill of your Opponent
This article is target to ranked solo queue.
You are not special
The vast majority of League of Legends players think that they have a superior level to their league, that they belong to a superior league. This can be sometimes be the case but for the vast majority of players it isn’t true. Most of the games you will play in solo queue you will have as team mates or opponents players at a similar skill level to yours. This is important for two reasons:
There is a concept in the chess or game or martial arts which is named “respect”. This mean that you take for granted that your opponent is as good as you. When you think he is doing a mistake keep in mind that your opponent is as capable of intelligent thoughts as you. A typical case in LoL is the bait, your opponent lets you think you have the upper hand, while his team mates joins the fight and kill you.
The chess game and martial arts are individual, but this rule applies to your team mates as well. Your team mate’s call is not necessary stupid, he may have information (no summoners on the enemy, or he noticed that the enemy mid was going bot) that you don’t have.
The second reason you may think you are better than your team mates/opponents is because of a cognitive bias. When you make a mistake (getting killed for instance) you will have at your disposal an entire range of reasons/excuses because of which you are dead. They can be valid. But the human brain is made so that you won’t be looking for such reasons/excuses for the mistakes of other players. Therefore your mistakes are much more forgiveable than others’ which leads you to think you are better.