Not everyone is prey to their emotions, I guess it all depends on how calm you normally are there is a main point that I disagree on though
1. Never /ignore another player on your team, the costs outweigh the benefits
As an example of our players was having issues with me (calling me a feeder, noob tank etc) however I honestly dont care what other people think of me so I just kept playing as per normal however our "team leader" riven decided to /ignore her for some reason, late game we took baron and she went to get blue while he was trying to get a team fight running, annie mentioned she was getting blue but riven couldnt see if so he engages 4v5 and we all die (annie tries to stop them at base and gets killed we lose inhib and 1 nexus turrent and of course we no longer have baron) we do however still win in the end, but ignoring a player means you are basically taking responsibility for determining their position and readiness for battle yourself.
Below are just my thoughts on bringing your emotions into a game enviroment in which the majority of people are too young to understand they might be bruising your precious ego when they call you out on mistakes you make
Some people have fewer issues with their emotions, I come from a variety of games and guilds in which trolling players for doing poorly on vent is common, I pretty much take it as a your are doing badly mate try and improve soon, so I just calculate how to best achieve my next goal (getting farm, stopping a player snowballing, assisting one of our players at snowballing).
I cant honestly say there are no negative effects to me doing poorly I can say there are no negative emotional effects to me doing poorly though, I went 0/3/0 to start a game once this meant my 2 lane opponents had a significant gear advantage early meaning that me and my lane partner had a few issues getting started as we had some very strong opponents but by co-ordinating our efforts (she stunned and I knocked up) we managed to get a few kills in retaliation against our opponents, I ended the game 6/14/21 which isnt an amazing scoreline but we won and thats all that really mattered, the point is once you cede early kills you have to critically look at what you can do now to improve your game, as if you just react emotionally and try and attain a quick kill without a plan behind it you will end up 0/4/0 or even worse in a short period, if there is no way to get a kill then tower hug and farm at the tower only until you have enough farm/assistance to get the kill.
3. Honestly if you are going to react emotionally in what is simply a game just because you are doing poorly you may wish to look more deeply into yourself and figure out what your main issue is as this is just a game winning and losing isnt a huge deal (unless your in a tournement I guess as then it would be more of a big deal)