History YMMV / TheHardyBoysNancyDrewMysteries

* AngstWhatAngst: Third Season. ''Last Kiss of Summer'' has Joe broken up and going on a revenge rampage to avenge the love of his life, who was killed in a car wreck as he was driving; she dies in his arms. Two episodes later, Joe's making out and flirting with other women as if nothing's happened, and the fiance' is never mentioned again.
* BigLippedAlligatorMoment: [[Series/CharliesAngels Jaclyn Smith]] makes a small appearance in ''The Mystery of the Hollywood Phantom'' as herself playing her character on Charlie's Angels. She ends up kissing Frank as he walks around a corner, an incident not mentioned again, and with zero effect on the plot.

* HarsherInHindsight: The 2nd season (1978) episode ''Arson & Old Lace'', where an arsonist torches a skyscraper, not only trapping Joe Hardy and a small child in an office room, but also trapping Frank Hardy and Nancy Drew in the penthouse, with an un-working elevator & access to the roof blocked. After helping panicked people find the stairs through heavy smoke and flames, Joe delays his escape to follow a cry for help & finds a trapped child. He shields a child from an explosion with his own body [[note]]The explosion blows out a window and a good part of the outer wall; the shot of this, taken from outside & ground level, looks disturbingly like something crashing through the building[[/note]], then convinces the child to jump with him out of the window, as the fire has cut off all escape routes. Post-9/11, this episode is now hard to watch: people on the upper floors of the WTC were not only trapped by the raging fires below them, but access to the roof was also blocked. Many of those jumped to their deaths to escape the fire -- this makes the child's wide-eyed trust in Joe's assertion that they'd be OK heart-wrenching in hindsight. On top of that, WTC security guards stayed behind, helping trapped people find their way to the exit stairs -- guards who lost their lives due to their heroic delay of their own escape. The episode had only been meant as a cheesy ripoff to ''Film/TheToweringInferno'', but still...
* SugarWiki/HeReallyCanAct: Creator/ShaunCassidy & Parker Stevenson, two good-looking, easy-going actors with one-dimensional characters who mostly quip back and forth in a show that's only bait for teenage girls, right? Then we get Third Season. Hoooo, brother, do we get Third Season. ''Last Kiss of Summer'' has Shaun sinking his acting teeth into the dark side of Joe Hardy with a vengeance, portraying a revenge-obsessed, bereaved man who tramples over everything & everyone to bring his fiance's killers to justice. On top of that, throughout Third Season, Parker gives us a doubting & conflicted Frank Hardy, who is constantly put into roles of gaining someone's trust & then breaking it (usually in a way that traumatizes the victim); ''Game Plan'' brings this to a head, as the show implies that Frank [[spoiler: might have betrayed his brother and the federal sting operation in order to run away with the BigBad, a woman he's show to truly love, if she had just told him the full truth about her escape plans]].

* NightmareFuel:
** The title sequence for Season 1 was easily the spookiest for an American family show in TheSeventies.
** In ''The Mystery of the Hollywood Phantom'' there is a very harrowing scene where Nancy is walking down an empty street at night, searching for a man in a [[MalevolentMaskedMen grotesque mask]] reminiscent of Literature/ThePhantomOfTheOpera's scarred face. As she walks down the street, to a spine-tingling score, we see the Phantom looking at her out of alleys and stairwells, while she doesn't see him.
** Practically the entirety of ''The House on Possessed Hill'':
*** The musical score is full of eerie [[OneWomanWail One-Woman Wailing]], [[PsychoStrings tense violins]], and [[OminousMusicBoxTune Ominous Music Box Tunes]].
*** The OminousMusicBoxTune referenced above, comes from a pair of pair of [[CreepyDoll windup dolls]] that move and play music when wound up. When Joe is searching the house looking for Stacey, he looks into an empty room and sees that someone has wound the dolls up, presumably Stacey. He leaves, and the dolls wind down and stop... only to start moving again, despite nobody winding them up.
*** Frank looks into a room and sees a pool table covered in balls. As he watches, one of the balls starts rolling, and knocks into another ball, all by itself. [[spoiler:This incident, like the musical dolls, is never given a rational explanation.]]
*** By the end of the episode, [[spoiler:the mystery seems all wrapped up, with Frank convinced that everything that went on in the house was caused by either Stacey, or the criminals that were using the house to store the money and the corpse of their partner. Joe seems less convinced, and looks back at the house as Frank prepares to drive the van away. As he watches, the ghost of the man who originally owned the house, recognizable from the SpookyPainting in the living room, [[RealAfterAll comes out and stares at them from the porch.]] Joe tries to get Frank to see it, but by the time Frank looks, the ghost has disappeared. Joe, terrified, tells Frank to just drive away.]]

*** By the end of the episode, [[spoiler:the mystery seems all wrapped up, with Frank convinced that everything that went on in the house was caused by either Stacey, or the criminals that were using the house to store the money and the corpse of their partner. Joe seems less convinced, and looks back at the house as Frank prepares to drive the van away. As he watches, the ghost of the man who originally owned the house, recognizable from the SpookyPainting of him in the living room, [[RealAfterAll comes out and stares at them from the porch.]] Joe tries to get Frank to see it, but by the time Frank looks, the ghost has disappeared. Joe, terrified, tells Frank to just drive away.]]

** In "The Mystery of the Hollywood Phantom" there is a very harrowing scene where Nancy is walking down an empty street at night, searching for a man in a [[MalevolentMaskedMen grotesque mask reminiscent of Literature/ThePhantomOfTheOpera's scarred face. As she walks down the street, to a spine-tingling score, we see the Phantom looking at her out of alleys and stairwells, while she doesn't see him.