* EarWorm: You know the one.
* EnsembleDarkhorse: Andy and his family were meant to be the focus, but Barney stole the show.
* LawfulGood: Andy.
* LawfulNeutral: Barney, Type II.
* ReplacementScrappy: Warren Ferguson. The guy didn't have an ounce of what made Barney so funny. The fact that he tried to fill Barney's role, but ultimately failed, is what made his character particularly unfunny.
* SeasonalRot: A pretty serious case. After Don Knotts dropped out of the show after the fifth season to pursue a film career, the series went on without him for three more years. Most fans dislike these episodes (easily recognized because they were shot in color) for being unfunny and moralistic. Without Barney to play off of, Andy loses much of what made his own character funny, and he becomes a rather solemn grump.
** Also, the sudden addition of new neighbors in Mayberry, such as Howard Sprague and Emmett Clark, really didn't help matters much either.