Along with the ex machina, there are various other ways to cheat the audience of your story by finding an easy way out of the central conflict. These include and are not limited to killing off a major character, creating a suddenly new rule in the mythology of your fantasy story, and discovering a sudden unexplained weakness that only the enemy suffers from. Killing off a major character without repeating my words from a previous part cheats the audience out of potential character development. Another path this cheap fix can take is ruining the rest of the story if the character was very likable. It is like forcing a character into the sidelines but irreversible. Creating a fake rule out of thin air goes in a similar path of the ex machina but more than likely will result in a plot hole. For example, suddenly giving evil ghost cats the ability to escape the Hell-like Land of No Stars in the Omen of the Stars arc of the Warrior book series will seem weird when in the past they have never done this before. The sudden weakness trope is a "gift" that is best explained from the movie Signs, where the invading aliens had the convenient allergy to water. A sudden discovery like the allergy to water takes away what could have been a strong climax to the plot and leaves the audience very underwhelmed. However, these three cheap escapes from the climax are nothing compared to the forced apology.
For those uninformed, the forced apology trope is when the main plot line is resolved with a simple sorry. Despite the well developed and well explained tensions between both sides of the conflict, simply saying sorry is enough for a lot of authors. That is far from the truth. Hatred can not be resolved by just saying sorry. You have to earn the apology through redemption that helps to make the past conflict be forgiven in some shape or form. Otherwise the audience is going to be annoyed that an epic climax was cheated out of them with very unrealistic circumstances.
As proof to how bad this trope is in fiction, say there was a conflict going on between character A and character B. The conflict started when character A went behind character B's back by spreading false rumors about them in their high school. The rumors character A spread were about character B kissing the boyfriend of the most popular girl in school. (In this situation character B can be both female and male depending on how you interpret it.) As a result character B is shunned in school, stuck in an endless cycle of dirty stares and even bullying by the popular crowd in retaliation. Character A's motivation towards this act was jealousy towards character B's likable personality, which had earned them many friends. Being introverted and shy, character A had few friends. They grew jealous of character B and thus created the rumor. Character B is then outcasted for the remaining parts of the school year, entering a deep depression as a result of the rumor's poison. They find out what character A did through a confession, angry at what the character had done for their own selfishness. Character B feels they cannot forgive character A for what they had done. The same character later gets a job at a summer camp where their happiness is brought back through their job as a CIT. But that happiness could be threatened by character A, who also is a CIT at the same summer camp. Eventually the two characters will have to confront each other for what has happened in the past.
Based on the information about both characters, how do you think the climax should play out? Should character B confront character A for what they had done, deciding holding a grudge against them will just repeat the cycle and to just go on their life even if forgiveness is not given to character A? Or should character A try apologizing for what they have done, immediately gaining the other character's friendship despite making their life a living hell for selfish reasons? If choice two sounds disgusting or even unrealistic to you, the discovery of the problems connected with a forced apology for the sake of the plot will make sense.
Forgiveness needs to be earned, both in fiction and in real life. Although many people might say forgiveness is the best thing, that is not always true. Sometimes there are actions that even the nicest person or character cannot overlook. In these situations forgiveness is not an easy task, if possible at all. Forcing emotion out of your characters is like drinking rotten milk. You will feel sick afterwards and the experience will be far from rewarding.