gomen yuuka
A Blue Archive meme about Yuuka being cuckolded by someone else (usually Noa) by stealing Sensei, who she has a crush on.
The meme is often accompanied by Noa's catchphase "I'm sorry Yuuka" (ごめユウカ - gomen yuuka), though this is used in a more passive aggressive manner.
Spin-offs of this meme include Gomen Noa (a role reversal), Gomen Hina (Sensei being stolen away from Hina, usually by Iroha), or Gomen Fuuka (Fuuka suffering at the hands of the Gourmet Research Society).