Chekhov's Fired Gun

Chekhov’s Gun ⁠ essentially says that unnecessary details should be penalized—more directly, if a gun is introduced in Act 1, it should be fired by Act 2 or 3. However, it is possible to, perhaps, misunderstand this narrative principle and apply it unnecessarily. I’ve seen this extensively in cheap media (most often television), where the MacGuffin gets some ridiculous backstory to “justify” it…