* CrowningMomentOfFunny: Fonzie's been using "Sit on It!" for years, to great reaction. When ''Marion'' of all people uses it on ''him'', the reaction from the crowd and Fonzie himself was priceless.
* CrowningMomentOfHeartwarming: Joanie and Chachi announce their engagement. Howard, the father of the bride, walks up menacingly to Chachi- "Chachi, I'm going to say something, and I'm only going to say it once: I like you. Welcome to the family." and holds out his hand. Also, when they tie the knot in the GrandFinale, when Howard thanks the audience for being with his family through all these years, and says "to Happy Days."
* EarWorm: C'mon, sing it with me: "[[TitleThemeTune Sunday, Monday, Happy Days...]]".
** The "Pumps Your Blood" song.
* GodModeSue: '''Fonzie'''. UpToEleven in later seasons as a result of {{Flanderization}}.
* HeyItsThatVoice: Apparently Ralph Malph ends up [[WesternAnimation/DungeonsAndDragons stuck in The Realm working for Dungeon Master]]. Who knew?
* ReplacementScrappy: Roger.
* TheScrappy: Roger.
** Chachi was ''always'' [[TheScrappy The Chachi]]. He was popular with the girls, but retroactively, amongst older fans? Please.
* SeasonalRot: It started out as a very cool, low-key show, then became the ideal version of a standard sitcom with a StudioAudience. It'd started getting worse (the Trope-Named Shark-Jump) even before Richie left, but only got worse after that. Fonzie got a temporary full-time girlfriend for one season, and things got increasingly worse with gimmicks and nonsense until a thankfully fantastic final episode.