YMMV / Happy Death Day

• Alternative Joke Interpretation: When Lori and Tree fight at the climax, Danielle comes by knocking, demanding to know what the hell's going on in there. Did she (correctly) suspect that they were fighting or, with their groans and grunts, that they were having sex?
• And You Thought It Would Fail: Many audiences agree that Happy Death Day was a surprisingly entertaining film that manages to achieve what it wants, against expectations (as advertising made it seem like it was a cheap try at a clichéd Jump Scare horror movie).
• Complete Monster: John Tombs is a Serial Killer who was on the run for the murder of six women across the country, boasting that there are over a dozen more victims that haven't been found. After a confrontation with the police and killing an officer, Tombs is neutralized and taken into the hospital for a gunshot wound. In one of the loops, when Tree comes to the hospital to give a warning that Tombs will escape, she discovers that Tombs already murdered a security guard. Tombs then guns down a secretary at the hospital and chases down Tree to kill her as well. When Carter stops Tombs from killing Tree, Tombs snaps Carter's neck just to hurt her. He later gleefully watches Tree hang herself when she decides to reset the day. During the penultimate loop, when Tree confronts Tombs, Tombs steals her knife and attempts to slit her throat, only to stop himself so that he can relish torturing her.
• Crosses the Line Twice:
  • After Tree figures out that she's forced to relive the same day every time she's killed, she decides to try to find the identity of her murderer. There is then a Failure Montage of her spying the suspects... and being killed during her investigations. Up until then, the attacks of the masked killer have always been suspenseful moments. During this montage, Tree's outright frustrated expression at one point makes them darkly hilarious.
    • During the same montage, Tree tries at one point to hit the killer with a baseball bat... Only to realize too late (after hitting the person) that the person walking behind her was her sorority sister Becky Shepard. And then she's killed. Again.
  • Lori being thrown out her window caps off a serious scene. But the smiley exchange student screaming in horror at a body splatting right in front of her makes it funny again.
  • The end credits feature a recap of some of the death scenes... with goofy postcard-like drawings.
• Ensemble Dark Horse: Tree's sorority sister Becky is very well-liked by the fandom.
• Genius Bonus: Coupled with Freeze-Frame Bonus. There are two books of Sudoku puzzles on the bedside table next to Tree when she wakes up. Sudoku puzzles get easier the more numbers you fill in, similar to how Tree's puzzle gets easier (somewhat) throughout the film by eliminating suspects and murder methods until she figures out who the killer is.
• Hilarious in Hindsight:
  • In this film, Carter is very selfless, even going so far as to sacrifice himself to let Tree escape from the killer. A later Blumhouse film also features a character named Carter, who is the exact opposite.
  • Tree finds a baby mask in Gregory's office, but it turns out to be a Red Herring. In the sequel, he is the Babyface Killer in another dimension. Maybe he gave Lori the idea?
• Hollywood Pudgy: One of the fixtures of the repeated day is Danielle mocking Becky for her weight, even though she's hardly bigger than the rest of the sorority sisters. Deliberately invoked, of course, to underscore Danielle's status as an Alpha Bitch and the cruelty of the sorority.
• I Knew It!: Some viewers of the trailers guessed that Lori is the killer, because the candle she drops to ignite the gasoline is similar to the one from the cupcake she gave Tree earlier, which is shown in the trailers.
• Jerkass Woobie: While Tree is quite dismissive and hostile towards a majority of the people around her, it's made clear that it's because of her inability to properly grieve her mom's death. She does eventually get better, but only through the Trauma Conga Line of dying horribly over and over.
• Memetic Mutation: "Byeeeeeee!!!".
• Moral Event Horizon:
  • The real killer never really crosses this until the penultimate loop. Tree is being sincere and kind to all the good people in her life, and she gives Lori a heartfelt apology, admitting that she's been a selfish loser and promising to be a better roommate. Lori appears to accept Tree's apology, but then the final loop happens, and it turns out that Lori still gave Tree the poisoned cupcake and freed Tombs as a backup plan in the penultimate loop. And in every loop, Lori is perfectly okay with the idea to release a dangerous Serial Killer on the loose to cover her traces and that in several loops she has no qualms about killing Innocent Bystanders, and all of this was because Lori is a Yandere who wants a married teacher all to herself.
  • Tombs crossed it before the film started, as it was confirmed he killed six women across the country and at least a dozen more victims who haven't yet been found.
• Narm Charm: As the straight horror film it was marketed as, the title of the movie sounds ridiculous. As the not-so-serious comedy horror it actually is, it's not too inappropriate.
• Narrowed It Down to the Guy I Recognize: Some viewers immediately suspected Lori, since other characters were more or less unknowns while Ruby Modine had become a regular in Shameless (US) the year before.
• Nightmare Retardant: In the trailer, Tree's fright at seeing the masked figure for the first time behind her would be understandable... if it weren't for the fact that the mask looks so goofy. Even better: That's the mask of the SCHOOL'S MASCOT. Though some people may still find it scary or disturbing, due to it firmly falling into the Unintentional Uncanny Valley.
• Spoiled by the Format: The Golden Path where Tree is helpful, drops her Alpha Bitch traits, and even shoots the killer dead could be a nice ending... unless you notice there are at least 15 minutes left.

---