OPPA XL

OPPA is an emote used to express frustration with something, as you can probably guess with the man smashing his keyboard
why the emote is used is in reference to XL, which is the abbreviation of Xiangling
Xiangling is usually taken as the basis for analysing how good a character is when talking about damage output and ease of use
as such, she gets mentioned so much that even mentioning her name is enough to trigger genshin players and move them to anger
so OPPA XL is basically used when XL is mentioned
the word AGANE (the incorrect spelling of again) is also used in conjunction at times as it's used to refer to her being mentioned all the time