An Easy Way To Get Away From Toxic Teammates
Everyone has bad days. This is a fact of life, and though they shouldn't do it, people will often take out their frustrations on others. This is something we see often in League, where people are frustrated with stuff and the real world, and have a chance to vent to strangers online with no real consequences. This is low end of the Toxicity Scale.
The high end, are people who constantly BM, Mock, Swear, Verbally Abuse, and Harass other players, every game, regardless of the situation. They will be toxic to their own team if they're doing poorly, the other team if their doing well, or both teams just because they can. People on this end of the scale can often be found charitably referred to as (and i note the irony of this) "The crown-prince of douche-bag, long may he reign." These types of players aren't fun to be around, either on their side or against. They bring down the morale of all other players and it can ruin the game. Now there are two easy methods for getting away from these players as much as possible though.
Method #1: If you played a game with a player on your team who was toxic, or against one who was so rude you would never want to team up with them. Once match is over in the post game lobby, you can right-click that players summoner name and select "Block Player." What this does is make it so they cannot message you, add you to their friends list, and you matchmaker makers it so you cannot be teamed up with them.
Method #2: If they are just being toxic beyond all control and will not stop harassing you in a game, you can pull open the all playing hub by holding tab while in game, and select the mute icon next to their portrait. Then for the remainder of the game you will not see any in game messages via team or all chat from that player. This can be a problem if they stop being toxic and are trying to actually communicate an objective, but that is a risk you may need to take.
Are either of these perfect solutions? No, it's unfortunate that either of measures should ever have to be taken. What a lot of people forget is this is a GAME, and while it's more fun to win than it is to lose, you should have fun just playing regardless of the result. If you're not having fun in a game when you/it is at its worst, it may not be the game you should play. I fully realize other players can completely ruin a single game for you, but that should never ruin the whole game for you. In a perfect world, the entire community (outside of the professionals who get paid to play it) would recognize it is just a game and that they should never put anyone down for doing well/poorly in it. But we're not there, and until we do, these are the best things you can do to make sure your playing experience is as close to it as possible.