I've already been taking therapy for about two weeks now. I've definitely made an improvement but I still have off games where my attitude is unacceptable. Anyone having similar issues? Is there a way (no joke btw) I can unbind the enter key?
Try mentally preparing yourself before you queue in. Make sure your expectations are realistic, understand and accept your team may have feeders/trolls/whatever. Try to have goals that don't depend on winning or losing, so you can practice specific skills and feel that youv'e gotten something out of even a totally failed game.
Remind yourself that your actions will effect how other people play, and behave accordingly, but also that you cannot control the actions of others, or force them to do what you want.
If you find yourself getting emotional, don't talk, even if you feel you have something useful to say. When you are getting ready to type something in, stop, and ask yourself if your comment is 1) game oriented rather than something against a specific player and 2) phrased in a neutral way, rather than something that will make a person defensive.
You want to focus on the outcome of the actions and words you use, rather than the emotions behind them. What will this accomplish?
What i find helps me is to just say it out loud instead of typing it in chat. Gets some of that out their and your team cant get mad at you cuz they wont even know you said it
I tend to mute everyone who potentially can and will tilt me ingame. I'm not really toxic, but I'm a very emotional person who reacts to negative behaviour really fast, be it comments in chat or decisions made on the map.
Also, I started focusing on teamfight champions over yolo-heroes. It might sound weird, but chances are, if you are able to help others, not only will it give you a good feeling about it, but you also show others that they can trust you and your team will likely start to make less mistakes, up to the point where you actually do work together. This might sound stupid to some, but being able to help others win a fight is more of a mental support than hoping to get fed as LB or Zed and jump onto the enemy carry every other second.
just flick the enter key out of your keyboard.
I've been bad too.
However, my issue is not my social behavior. When I get matched up with a premade 4 and before minions even spawn they're flaming, refusing to help, won't ward against invades when I ask and we get invaded, etc, I sometimes quit if they're actively trying to prevent me from succeeding. Its exclusively a premade 4 issue, but its still a bad thing to do.
Before anyone says it, I know I should just finish the matches and report, but sometimes you're already fed up with something and don't want to deal with that for 20 minutes. Not an excuse, just my reasoning. Not trying to defend what I sometimes do.
Sorry to all of my opponents who had an unsatisfying victory due to that, even if the only time I ever do it is in normals.
I've been having the same issue lately. Always feeling the urge to type a critical comment or insult the bragging opponent.
I've found one thing that helps though. Whenever I feel like raging over an afk, troll or toxic player I just ask myself: "What would 
do?"
Ask a Rioter via the support page (support page is a SEPARATE account than boards account) to give you a permanent chat restriction.
Take a second to consider before typing something: Is it REALLY WORTH to use my time to say this?
You'll find that a good portion of the time, and probably almost all the time you'd have something negative to say, the answer would be no.
