lol
to op: deep breathes. I have sever anger management problems, and I play LoL, so as you can imagine it can be tough for me.
Tips: stress balls ( I use these mostly to throw at walls as hard as I can or to squeeze)
Just Don't: No need to comment anything. (you don't have to say you are wrong. the other person WON'T listen to you NO MATTER WHAT. You won't change a 13 year old trolls mind I can tell you that. Just don't type in chat This is very very hard sometimes)
Drugs/alcohol: Keep you a little calmer ( if Alcohol: don't play ranked, if any drug besides bud: don't play ranked, even if you think you can fail at nothing. If toasted off your ass then don't play ranked even though you think you can do it.)
Lastly I recommend using that sad lonely mute button that never gets used.
One last thing: never trust an Anivia, secretly they are always trolls... waiting to force you into a 1v5 with their walls. smiling, laughing evilly at your attempt to escape.