- Adaptation Displacement: More people know this movie than the play or the book.
- Alternative Character Interpretation: The film pushes the question of whether Rhoda's sociopathy is influenced by her serial killer grandmother's genes or from being spoiled rotten all her life, though more likely it's a combination of both; her genes may have not affected her so much had she not been spoiled and led to believe she should have anything that she wants. Christine, after all, has those same genetics and turned out fine, relatively.
- Has Rhoda really been spoiled, at least by her parents? Christine tried to make Rhoda accept the loss of the medal graciously and seems concerned that Monica keeps showering Rhoda with gifts. Moreover, other than her well-hidden sociopathy and penchant for murder-for-profit, Rhoda is a perfectly obedient and well-behaved child who seldom does anything that requires anyone to discipline her.
- When the adults were discussing "environment" as the primary cause for people's evil behavior, they may have meant the opposite: that ill-bred adults tend to have terribly abusive and deprived upbringings. In effect, they turn sociopathy into a classist phenomenon that happens to other people who are poorer and more prone to bad behavior. Rhoda, in contrast, has been brought up well with loving parents, and therefore should be safe from the temptation of criminal behavior. She proves their theory is wrong in this instance.
- Award Snub: Went 0 for 4 at the Oscars, with nominations for Best Actress (Nancy Kelly as Christine), Supporting Actress (Patty McCormack as Rhoda, Eileen Heckart as Hortense) and Cinematography. Heckart later won Supporting Actress for Butterflies are Free in 1972.
- First Installment Wins: The 1956 movie adaptation is the most famous and most fondly remembered as a psychological horror classic. There have been two other remakes since then... and that is all that people generally know about them if they are ever fortunate enough to be mentioned.
- Narm Charm: The hammy acting and the more outlandish elements of the story easily could've derailed the film, but it's well-made enough that, coupled with Refuge in Audacity, it works. Some of it even moves into Camp territory, with the Rhoda/Leroy confrontations being the prime examples.Rhoda: You tell lies like that, you won't go to Heaven when you die!Leroy: They got a little blue chair for little boys and a little pink chair for little girls!
- Nightmare Fuel: Everything. About. Rhoda. EVERYTHING.
- Leroy being set on fire, and his death. All you hear of it is his screams and all you see of it is the smoke, but it's still horrifying. Christine is distraught, and she cries and screams, but not before having a Thousand-Yard Stare at the realization that it's too late. Monica, being ever ignorant and insensitive, belittles poor Leroy's death and is only concerned about Rhoda, who has done the evil deed. And as this whole nightmare is going on, Rhoda plays Au Clair De La Lune very loudly and very quickly on her piano, much to Christine's misery.
- She's Just Hiding: We never do see Rhoda's body after the lightning strikes the pier, though that could be because of censorship at the time or the fact that that bolt of lightning incinerated her body to ash. There's also a splash in the water just off the pier about two seconds after the lightning bolt.
- She Really Can Act: Patty McCormack! This little girl really sells the murderous Enfant Terrible thing she's got going on.
- Sympathy for the Devil: Make no mistake: Rhoda is awful. But as Tasker points out, this isn't something she chose, nor does she have any ability to stop herself. Part of Christine's agony comes from realizing that even if Rhoda could somehow be prevented from killing, she would still have no capacity to truly love.
- Leroy was no saint, and he was quite mean and conniving, but he was visibly afraid of Rhoda the moment he realized that he was bullying a murderer. And those cries of despair as he was burning to death really tugs at the heartstrings.
- The Woobie: Christine, and especially Mrs. Daigle, who only has vague suspicions about what really happened to her son that no one takes seriously.
YMMV / The Bad Seed (1956)