Kill Your Darlings - Uh, Define Darlings!

Kill your darlings is a term frequently used in writing that I’ve seen interpreted many different ways. So I went in search of the true meaning of kill your darlings.
Urban Dictionary:
Kill your darlings “In writing, you must kill your darlings.” --William Faulkner

This literary advice refers to the dangers of an author using personal favorite elements. While these may hold special meaning for the author, they can cause readers to roll their eyes for reasons such as:

-Purple prose 
-Narm ...