The world of Mystic Falls and its inhabitants was filled with magic, mayhem, and all things supernatural, which was what made The Vampire Diaries so appealing. That said, certain details in the winding eight-season-long fantasy show were a tad too strange, and fans couldn’t quite wrap their heads around it. These aspects of the show were confusing to follow, or they broke established lore rather blatantly.
Whether it was Bonnie’s sudden lack of observation skills as the Anchor to the Other Side, or Lexi’s sudden compassion towards the man who murdered her, these TVD details were absurd in more ways than one. They made fans act out of character, and even destroyed iron-clad rules of the TVD world. Fans would have appreciated some clarity on these points, or some kind of retroactive explanation might have made them a little less bizarre.
Logan’s Lack Of Invitation Into His Own Home Was Baffling

Logan was a side character in The Vampire Diaries, and he probably wouldn’t even be remembered had it not been for his bizarre invitation scenario on the show. Jenna’s former boyfriend was known to be quite obnoxious, and he became even more so when he became a vampire. In a darkly funny twist, Logan was not able to enter his own home after he transitioned completely.
Logan Fell was a member of the Fell Founding Family of Mystic Falls.
Now, vampires could not enter homes that they were not invited into in The Vampire Diaries as a rule, but it was puzzling to see that Logan could not get into his own house. Sure, he was a vampire, but his name would also be on the sale deed of the house. This was why it made no sense that he could not enter his own home, and there was no explanation given about Logan living in someone else’s home for this.
Lexi Chose Not To Come Back To Life For Her Murderer
The entire Mystic Falls gang jumping towards death in Season 5 of The Vampire Diaries was a shocking plot twist, but they had were all expected to return from The Other Side because Bonnie was the Anchor. However, things went awry when they actually reached the Other Side, and there was plenty of discourse on who deserved a second chance at life after their death. Fans were delighted when they saw Lexi, as this was the perfect moment for her to resurrect and become a part of the Mystic Falls gang.
Damon had chalked out an elaborate plan where he attacked two humans, and compelled them to paint Lexi as their attacker. Damon then staked her when she retaliated.
However, Lexi acted rather bizarrely when it was her turn to pass through Bonnie. She abstained from doing so, stating that she would be a bad friend to Stefan if she did not allow his brother, Damon, to come back to life before her. The sentiment was noble, but not when Damon was the very person who murdered Lexi. She essentially sacrificed her life (again) to help the man who had staked her in cold blood, and that logic gave fans a headache.
Katherine Doesn’t Die, and Bonnie Doesn’t Notice

Nobody could foresee Katherine turning into a human, but when she got cured, she had no choice. This left her weak and vulnerable to her many enemies, but things got worse when Silas drained her of the Cure so that he could be with Amara. Katherine started to age rapidly, and everyone was sure that her end was near.
Katherine was born into the Traveler coven before she turned into a vampire.

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However, Katherine being Katherine did not go easily into the void, and she came up with a plan to Passenger herself into Elena’s body successfully. The detail here that didn’t make sense was that Bonnie was the Anchor, and she would have definitely felt Katherine’s passage into the Other Side. When she didn’t pass through her, Bonnie should have known that something was wrong. However, the Bennett witch did not sound any alarms, nor did she even seem to realize that Katherine had not died when she had pretended to.
The Salvatores, Elena, Matt, And Jeremy Took Down An Original, Each

The Vampire Diaries had established very quickly that the older a vampire was, the stronger they would be. So, an Original, who was the first vampire ever, would be virtually unbeatable. However, the youngest vampires, a newbie vampire hunter, and a human were able to take down three different Originals each. Elijah was temporarily, but rather easily staked by Damon and Stefan in their first TVD fight, and even Elena daggered Elijah by tricking him.
Elena was a new vampire when she aided Jeremy in killing Kol.
Even more strangely, Matt, who was a human, was able to stake Finn in the heart with the White Oak Stake, and Jeremy was also able to do the same with Kol, with Elena’s help. Considering how formidable Originals were supposed to be, this should have been impossible. Still, it did not happen once, but nearly four times, which made fans question how powerful a 1,000-year-old vampire would be, compared to one that wasn’t even two centuries old.
Vervain’s Efficacy Was Doubtful

In the TVDU, vervain was a vampire’s biggest weakness in more than one way. Most importantly, a human on vervain could not be compelled into submission by a vampire, which was why Elena wore it at all times. Secondly, vervain or vervain infused water would debilitate a vampire by burning them, or rendering them lifeless for a short period of time, depending on how much they consumed. These rules were promptly thrown out of the window as the show progressed.
“I’m wearing vervain, Damon. It’s not going to work.” – Elena Gilbert
Vampires like Katherine would consume vervain in order to build resistance to it, which completely undid the herb’s potency. If vervain could be microdosed and resisted, then vampires were virtually impossible to beat. Moreover, vervain was supposed to first be a rare herb, then it was suddenly widely available in the town. Everything related to vervain was wildly contradictory in TVD.

The pilot episode of The Vampire Diaries depicted a lethal version of Damon Salvatore. Stefan’s older brother was able to control the weather, control animals, and possibly become one himself when he was first introduced. His telepathic powers with Caroline were also much more potent, as he could make her do his bidding from a distance.
Damon in the books had all these powers, and shapeshifting abilities in the books.

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However, his powers seemed to vanish without explanation as the show progressed, with no sign of mysterious fogs, winds, or crows. He was rather good at compulsion and mind control, but this was also forgotten once his arc with Caroline was done. This made fans question just how dangerous Damon really was, especially with powers that came and went.
Bonnie Was Able To Cure Stefan With A Syringe

Another powerful object that had shaky lore was the Cure. At first, there was only a single dose of the Cure, but Bonnie was able to surpass this cleverly by extracting one from the Prison World, which was an identical copy of the real world. Then, Silas made it clear that for the Cure to pass from one to the other, the previous drinker would have to be drained completely, till the point of death. He then proceeded to do the same with Katherine.
Damon was due to pass on the Cure to Rebekah when he was on his deathbed.
However, later in the series, Bonnie was able to Cure Stefan with just a syringe full of the Cure from Elena’s bloodstream. Further, Stefan also cured Damon with one injection in the Season 8 finale of the show. The rules set by the show were broken by it blatantly, and thus created big plot holes regarding previous storylines every time the writers did this.
The Petrova And Salvatore Doppelgängers Were Supposed To End Up Together
Elena was one of the Petrova doppelgängers, but Stefan being one himself was a big surprise. Then, Markos revealed that the Petrova and Salvatore doppelgängers had always ended up together, as they were tied together by nature and fate. This had happened over and over in the world, but not with Stefan and Elena.
While they dated each other, Elena chose to be with Damon much before Markos even came into the picture. This meant that the “tie” between her and Stefan did not exist, and even Katherine did not end up with a Salvatore doppelgänger. TVD could have just not introduced these plot points, especially if they were going to surpass and break them later on.
What Really Was Enzo’s Fate?

Enzo got the worst end of the stick when he was killed mercilessly by Stefan, just before he got his happy ending with Bonnie. However, Bonnie in her grief created an alternate dimension for Enzo, where his soul was housed after his death. In the concluding scenes of the series, Enzo was seen in this dimension, unable to be seen or heard, but he was felt by Bonnie.
Enzo had been abandoned by his family, and turned into a vampire by Lily Salvatore.

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This begged the question — what really was Enzo’s fate? He was trapped in a dimension by himself with no company, and this sounded more like torture than a happy ending. He could have gained peace instead and be with the others in the afterlife, but he was kept stuck by himself just to be around Bonnie. The nature of their relationship was also puzzling, because it wasn’t clear if they stayed together in this broken manner, or Bonnie was allowed to move on.
Damon And Stefan’s Afterlife Assignations Made No Sense

At the very end of TVD, fans saw Elena in the afterlife with her family, which made a lot of sense. However, Damon and Stefan gaining eternal peace was very nonsensical. They had committed way too many crimes against humanity to get away without punishment, which were not limited to killing pregnant women and annihilating entire villages.
Damon and Stefan had been vampires, cured humans, and spirits in their lifetimes.
This was why fans found it awkward to see them painted as good guys who got the same fate as Aunt Jenna, who had never even hurt a fly. It might have made more sense for the afterlife section to be completely canceled from the finale, as it made no sense. Damon and Stefan were not anti-heroes when it came to the body counts they racked up — they were total villains.