Syndrome's Law 

The viewpoint that, if every individual item can be defined as , then none of them do.
The term comes from the 2004 Pixar film "The Incredibles", wherein the main antagonist, Buddy "Syndrome" Pine, states,
"... when I'm old and I've had my fun, I'll sell my inventions so that everyone can be superheroes. Everyone can be super. And when everyone's super, no one will be."

"If every character is broken and overpowered, then none of them are"
That's what's referred to as "Syndrome's Law"

Syndrome's Law by JKPwnage January 19, 2019

Law & Order Syndrome 

The term "Law & Order Syndrome" refers to an actor or actress who appears in a long-running series as a guest star but later appears in the series as a permanent character. The term is derived from the famous television series "Law & Order", where a numerous number of actors/actresses who are currently playing the main detectives/lawyers have appeared in a previous episode several years beforehand as a completely different, temporary character.

Mike: Wait, Chris Noth is a detective now? Wasn't he some random nameless guy in the last season?

John: That's a case of Law & Order Syndrome, Mike.

Law & Order Syndrome by IMuckedYourFom October 5, 2012

Lawn Gnome Syndrome 

n. A mental ailment similar to depression, characterized by a tendancy to mope and be unhappy.
Acronym: LGS.

A: "He's sitting in the corner all alone moping. What's wrong with him?"
Dr. B: "He has Lawn Gnome Syndrome. Go and force him to feel better."

Lawn Gnome Syndrome by qqq March 29, 2005