Conversely, shows that have "low Dexter Ratings" (i.e., good endings) are held up as counterexamples: Breaking Bad (ended perfectly on its own terms), The Americans (quiet, devastating, logical), Six Feet Under (the gold standard of finales).

That ending—the Lumberjack Finale—became instant shorthand for narrative cowardice. It wasn't just bad; it was illogical, unsatisfying, and laughable. Thus, the "Dexter Rating" was born.

While no strict mathematical equation exists, fans and critics use a weighted, qualitative formula:

In the lexicon of "Peak TV," the fourth season of Dexter stands as a towering achievement. It remains the benchmark by which all modern thrillers are measured, and it is the primary reason the show’s "average" rating remains deceptively high on aggregate sites like Rotten Tomatoes.

The TV-MA rating for Dexter comes with several content descriptors, which provide a more detailed explanation of the show's content: