There are many factors that contribute to how strong of an impact a most disturbing horror movies.

Usually, these movies are not the happiest stories you can find on screens, and not just because of a tragic ending. They are intense, challenging, and sometimes even shocking. In their daily life, people seek refuge in movies, but these sorts of titles provide everything but that. They offer something different: uncomfortable questions, doubts, and occasionally, unnerving truths. Although they are not common, there are several movies you should watch only one time.

10 We Need To Talk About Kevin (2011)

Directed By Lynne Ramsay

The acclaimed psychological thriller drama features Tilda Swinton as Eva, an initially reluctant mother who is forced to come to with a profoundly upsetting realization: the devious nature of her son, Kevin (Ezra Miller). We Need to Talk About Kevin is a highly disturbing tale that is both saddening and terrifying, emphasized by the brilliant acting work of Swinton.

The movie touches upon one of the most hidden yet intense fears that a parent can have.

Although it is never specified, Kevin displays many of the symptoms typically associated with psychopaths. The movie touches upon one of the most hidden yet intense fears that a parent can have. The brutality and cruelty of Kevin's actions are hard to digest, even harder to forgive, but what makes the story so upsetting is how his choices as well as him as a character are presented through the eyes of a mother. As much as the movie is well executed, it is better to only watch it once.

9 American History X (1998)

Directed By Tony Kaye

American History X is a raw, superbly performed movie that gave Edward Norton the opportunity to fully shine as an actor while delivering important lessons on tolerance, ignorance, and forgiveness to the public. The movie is exceptionally clever in depicting the roots and consequences of hatred in society, offering universal teachings in a deeply personal manner. However, the film is also terribly cruel and unforgiving.

Through a profoundly personal portrayal of a family, American History X offers the public an accurate societal analysis. It is perhaps because of the heavy emotional weight the film assumes through the depiction of the two brothers, the main characters, and their approach, refuge, and detachment from hatred that the story is not simply dramatic but is also an emotionally draining watch. The finale, as tragic as it is likely, gives the audience one final, cruel lesson.

8 No Country For Old Men (2007)

Directed By Joel Coen & Ethan Coen

Written and directed by the Coen brothers, No Country for Old Men is a cinematographic masterpiece that features a stellar cast that includes Tommy Lee Jones, Josh Brolin, and Javier Bardem, the latter as one of the best film of the Coen brothers.

However, it is not a comfortable, or easy, watch. Therefore, although the story is certainly worth exploring in some specific circumstances, it is mostly not worth visiting again. The story demonstrates themes like fate, causality, and self-agency through the portrayal of a hunter (Barden), and the hunted (Brolin).

The film delves into the concept of evil not in the emotionally intense way American History X does, but through a more detached perspective that, like the main character suggests, is what allows people to navigate the cruel world we live in. The movie's uncomfortable philosophy is likely to leave viewers at least partially upset by the ending.

7 Requiem For A Dream (2000)

Directed By Darren Aronofsky

Requiem for a Dream is only one of a long list of beautifully made movies that explore the world of drugs. When discussing such a delicate yet often discussed subject through an artistic medium like the cinema, it is important not to fall, even accidentally, into the trap of the glamorization of the issue.

In the case of Requiem for a Dream, the director did not even come close to it. The film features three characters inevitably interlinked with each other as they face the haunting consequences of their addiction. The story, divided into three parts — summer, autumn, and winter — is incredibly bold in representing the worst side of that world, showing the characters at their lowest points, with barely the chance to rise back.

The initial illusion of promises of happiness, obsessive attachment, and subsequent desperation are so well-crafted and portrayed that the movie is perfect at delivering its lesson. However, because of its wickedly realistic execution, you may only want to watch it once.

6 Midsommar (2019)

Directed By Ari Aster

One of the most disturbing horrors of the last few years, Midsommar, written and directed by Ari Aster, tells the story of an American couple who gradually fall under the influence of a violent Swedish cult. The main character, Dani, played by Florence Pugh, is a traumatized young woman who has just lost her entire family due to her sister's suicide via carbon monoxide poisoning. The movie explores themes of grief, emotional control and manipulation, as well as globalization.

Despite the movie's intelligent execution, it is one of those stories that can only be handled once. Dani's descent into submission under the new "family" she craves and finds is not only painful to watch but also deeply unnerving and crude. By the end of the movie, the character might have deluded herself into believing she found the love she was looking for, but the terrible price she paid is haunting.

5 Hereditary (2018)

Directed By Ari Aster

The filmography of Ari Aster is a testament to the director's ability to deliver one-time killing blows through beautifully crafted films that haunt the public back to their normal life. Hereditary is one of Toni Collette's best movies — for which she was famously snubbed for an acting nomination — an incredibly well-written story, with stellar performances, and a deeply upsetting resolution.

However, given the disturbing plot and incredibly brutal scenery, Aster's horror masterpiece will also probably only be watched once per person. The movie explores delicate yet universal themes of grief with an emotional resonance and sophistication that goes beyond being a jump-scare type of movie, using relatable experiences of pain and sorrow to terrify the audience in more subtle, twisted ways.

As great as the story is, there is no doubt that it is also upsetting in the most poignant way, insinuating itself in the mind of the viewer. As a consequence, the public does not need a reminder of the film every now and again, because it is likely that it will never leave their mind.

4 Melancholia (2011)

Directed By Lars von Trier

Written and directed by Lars von Trier, who is certainly no stranger to crafting highly controversial films that leave a bitter taste in the mouth of the viewer, Melancholia is a dramatic, catastrophic story explored through the perspective of two sisters. As a suspicious planet approaches the earth, the narrative unfolds depicting Justine (Kirsten Dunst), a depressed young woman, and her sister Claire (Charlotte Gainsbourg), a happily married mother.

Von Trier plays with humanity's often buried fears of annihilation, finality, catastrophe, mortality, and inability to escape fate, haunting the audience long after its tragic conclusion.

What is harrowing about Melancholia is that it provides absolutely no hope, as they gradually come to the realization, through the character of Claire, that there is nothing they can do but accept the complete destruction of the earth. Von Trier plays with humanity's often buried fears of annihilation, finality, catastrophe, mortality, and inability to escape fate, haunting the audience long after its tragic conclusion.

3 Manchester By The Sea (2016)

Directed By Kenneth Lonergan

When it comes to sad movies, Manchester by the Sea certainly deserves a high spot in any ranking. The film, directed by Kenneth Lonergan and interpreted by Casey Affleck and Lucas Hedges, tells the story of Lee Chandler, a depressed and asocial janitor, who is given legal guardianship of his 16-year-old nephew Patrick after his brother suddenly dies of a cardiac arrest.

However, this is not the first time Lee has lost a loved one. The film is another upsetting exploration of grief in the most harrowing, hopeless way, showcasing themes related to guilt and PTSD. Manchester by the Sea is not a story about moving past one's trauma and embracing the future.

On the contrary, the movie delves into the idea of grief as a persistent presence that sometimes will not leave and is set to shape every future choice and action of a person. Instead of the perseverance of the human spirit, the story explores the perseverance of grief, balancing with more delicate, even ironic moments. As beautiful as it is, however, the raw sadness that characterizes it can be a lot to process.

2 Grave Of The Fireflies (1988)

Directed By Isao Takahata

An animated Japanese movie produced by Studio Ghibli, Grave of the Fireflies is based on a semi-autobiographical short story by novelist Akiyuki Npsaka. Hailed as one of the best war movies ever made, Grave of the Fireflies tells the story of siblings and orphans Seita and Setsuko as they attempt to survive the final period of the Pacific War.

Grave of the Fireflies has a 100% rating on Rotten Tomatoes.

Studio Ghibli would go on to produce many more stunningly animated movies with profound and potentially upsetting themes, but all with a lighter heart. In this case, the emotional reaction of the viewer is an indication of the heartbreaking nature and evolution of the story. The two main characters suffer the consequences of faults that do not belong to them, as two kids without protection — all they have is each other. Their journey culminates in a tragic finale that is both realistic and emotionally devastating.

1 Uncut Gems (2019)

Directed By Benny Safdie & Josh Safdie

Uncut Gems, often considered one of the best films of the 2010s, is an anxiety-ridden story that shows Adam Sandler at its best as an actor. The movie follows Howard Ratner, an American-Jewish gem dealer and gambling addict, who has to retrieve a precious gem in order to pay off his debts.

The film portrays Howard in a deeply compromising and difficult situation. Given the excellent execution and performances of the main actors, the film was both critically acclaimed and a success at the box office. Nevertheless, the movie is another one of those stories that should possibly be watched only once.

The chaotic unfolding of the events keeps the viewer constantly on edge, with perfectly crafted suspense in every scene. To add to the already emotional turmoil it creates, Uncut Gems appears to end on a positive note but shortly after falls within the tragedy that the viewer expected, from the beginning.