"feelings yakuza" is an internet slang term referring to "those who turn their personal discomfort into a social evil and try to erase the target completely". It has been used in proship/antiship discourse.
Typically, Americans will harass Japanese artists for being proship or pedophiles for what they draw. It's a concept that may be difficult to understand in Japan, where all fictional depictions are allowed, it's not good to insult someone's work, and people are looked down upon for not being able to distinguish between fiction and reality.
"I got a message from an Americantalking about proship"
"Don't worry about it, those are just American feelings yakuza."
Late Night Feelings are those melancholic feelings that you get when you're alone at home as night grows later and later. Caused by beeing sleepy, they disappear the nextmorning and make you feel like a retard.
1: What a beautiful night! How are you?
2: I don't know, I feel odd. Damn late night feelings.
This phrase makes an appearance in Phoenix Wright: Ace Attorney - Turnabout Samurai. It is stated by the best prosecutor in the Ace Attorney series, Miles Edgeworth.
Unnecessary Feelings has a celebration day on 20th October, usually people will make fanart of the scene and post on social media to celebrate.
Miles Edgeworth: Thanks to you, I am saddled with unnecessary... feelings.