Avoid endings that are too rushed or feel forced. Give the characters and plot enough time to develop naturally. Also, don't introduce new major elements at the very end that come out of nowhere.
Well, a bad ending can be the betrayal of a trusted friend leading to the downfall of the main character. In many crime or mystery stories, this is a common trope. The main character, who trusts someone blindly, gets double - crossed. Another type of bad ending is when there is no resolution at all. The story just ends in a state of chaos and confusion, leaving the reader frustrated. For instance, some experimental stories end this way.
One common element is a sense of loss. In most bad endings stories, the characters lose something important, like in 'The Necklace'. The woman loses years of her life trying to replace a lost necklace. Another element can be a lack of redemption. The characters often don't get a chance to make things right. For example, in 'Macbeth', Macbeth's actions lead to his downfall and he doesn't get to redeem himself. And sometimes, there's an element of fate or inevitability. It seems like no matter what the characters do, the bad ending is coming, like in 'Oedipus Rex' where he tries to avoid his fate but still ends up fulfilling it.
As a person who loves reading novels, I have not actually read all literary works. However, some classic literary works did have bad endings, such as One Hundred Years of Solitude, The Catcher in the Rye, The Great Gatsby, and so on. These works might be incomplete due to the author's unfinished state or problems in the creative concept.
Although these works may have bad endings, they are still regarded as classic literary masterpieces because their status and influence in the history of literature cannot be ignored.
Bad endings can make the reader feel sad or disappointed. If they've been rooting for a character and that character meets a tragic end, it can be quite a downer. For example, when a beloved hero dies, it leaves the reader with a sense of loss.
The story of 'Frankenstein' has a rather dark ending. The monster created by Victor Frankenstein is rejected by society and his creator. In the end, the monster vows revenge and kills many of Frankenstein's loved ones. Frankenstein chases the monster to the Arctic, but in the end, he dies, and the monster, filled with regret, disappears into the ice, leaving a trail of destruction and sorrow.
The following were all animes with bad endings:
" Sword God Realm ": The protagonist, Kirito, was unable to be with the girl he liked, Asuna, which eventually caused him to be unable to enter the virtual reality game and lose everything.
2 " Gate of the Stone of Destiny ": The protagonist, Okabe Rentaro, traveled through time and space to save his girlfriend, Rena. However, the experiment failed and led to his death. Rena was unable to save him.
3 " April Is Your Lies ": The protagonist Shinji Miya committed suicide because he couldn't meet his mother, and the heroine Kaoru Miyasen never understood his feelings.
4 " Evil Crown ": The love story between the protagonist, Guang Zhi, and the heroine, Gui Yanye, is full of sadness and regret. In the end, the two of them separate.
5 "Even a chuunibyou disease wants to fall in love!": The relationship between the protagonist, Nobita, and the heroine, Sakura, was full of contradictions and misunderstandings, which eventually led to their separation.
The endings of these animes were very tragic and regretful.
In some cases, the good boy and the bad girl may become friends. The good boy's positive influence helps the bad girl to reform, and they end up having a great friendship where they support each other's growth. The bad girl may learn valuable lessons like kindness, honesty and respect from the good boy. And they might go on to have a positive impact on others around them as a team.
One possible ending could be that the main character overcomes the initial bad situation and gains a new perspective on life. For instance, if they were in a car accident (bad thing), they might end up being more grateful for every day and start living life to the fullest, which is the best outcome.
I recommend "The Immortal Music of the Zither" to you. It's a classic Xianxia novel with a tragic ending. The female protagonist Qin Zheng had transmigrated to become the female protagonist of the novel. In order to get rid of the tragic ending of the original female protagonist, she gave up the female protagonist's golden finger and embarked on a new path of cultivation. However, on the path of cultivation, she still encountered the teasing of fate, and her ending was quite tragic. I hope you like this fairy's recommendation. Muah ~😗