I actually think that majority of players just spam mastery icon for some form of self irony after they make a mistake
My favorite is when you're farming top peacefully, your jungle comes in, engages a fellow farmer, dies almost instantly, then flashes mastery 7.

I hope you have a nice day. https://img.gifamerica.com/1e59e80b8b4c4ea6ac4759faabab3457_you-mad-gif-u-mad-bro_400-400.gif
I get a laugh every time someone flashes mastery 7 just a second before they die
That's not fair. Yasuo may go 0/13/0 by 16 minutes but he'll at least have way better CS than that. Come on now.
Spamming mastery emote, while running wildly is best part about playing nunu.
My faverouite is when the entire team flashes mastery while sieging mid inhib turret. Then we die and throw the game .
Ah that's always the most fun time to do it.
I just got my teammate and myself killed as Lee flash-kicking a terrible target into them? Time to spam that mastery emote. I just suicided 1v9 as Vayne? You better believe that mastery emote is coming out.
Nah I use mastery emote out of irony when i mess up! [slayer-pantheon-thumbs]
Pshhh...I don't even know what the command is so I couldn't do it for ANY reason. lol