There should really be a way to mute emotes/mastery flash/ etc.

I'm fine with casual banter, when I'm in a decent mood. It's fine if a player wishes to express themselves - but it becomes really annoying if used incorrectly. I normally refuse to flash mastery unless the enemy has really made me angry enough to do so. Or, I just made a cardboard level mistake and I flash it out of irony.

Riot was going in a good direction when they allowed people to mute pings. The main argument against it was that it may stop the bad WITH the good. The same cannot be applied here - mastery and emote expressions are both social. You don't need a mastery flash from your enemy to read anything other than how much they love being narcissistic or that one guy just died and flashes mastery out of irony.

My point is just to say "hey, why not take the same treatment of pings to the bm-heavy mastery emote system." Though, I don't know why it can't be muted in the first place - a bit of a odd choice now that i think about it. There's probably a lot of scripting involve in this, but its just a request.