A lot of questions are flying around about whether or not got canceled, especially since fans still love watching back the original series with its cornucopia of well-developed characters who ranged from good to evil, and definitely fell into the grey areas in between. Irrespective of the morality of each character, their personalities changed when they interacted with each other and the Mystic Falls gang.
Many a time, the good guys could be pretty unkind, which could be surprising to audiences. Some of the meanest characters in the show were the usual suspects, like the elder Salvatore and villainous Kai. However, many minor characters and Good Samaritans of Mystic Falls also fell onto the meaner spectrum and did some unkind things to one another.
Kelly Donovan
Matt's mother was always a contentious figure, mainly because of how neglectful she was of both her children. Many human characters on TVD were evil, but Kelly managed to be terrible both as a human and as a spirit. She thought it was appropriate to hook up with people who were Matt's age and abandon them whenever she felt like it.
When she returned to Mystic Falls in season 8, she had no qualms about hurting people to get what she wanted, and blamed Matt for not caring for her, even though she was the parent. Kelly was a nasty piece of work.
Tyler Lockwood
On the surface, Tyler seemed to be a regular ol' werewolf, but his actions from the beginning of the show until the end were selfish and mean. He was a really bad partner to Vicki and used her for his benefit, and when Caroline helped him transition into a wolf, he handed her over to the other wolves to be tortured.
He then neglected his relationship with Caroline to get revenge on Klaus which was horrifically unfair to her and then tried to harm several of his friends along the way. Tyler also bullied Jeremy and got too angry too fast, making him a very unlikeable character.
Damon Salvatore
This vampire made rudeness his signature move, and he had no reservations about attacking Stefan's friends, killing Elena's family, snapping his best friend's neck, and threatening Bonnie and several others over and over again.
Giving rude nicknames was a typically Damon thing to do, and he was proud of his lack of tact and manners. Using people, compelling them, killing them, and double-crossing friends was an everyday affair for him, and he only improved a bit once he started dating Elena.
(Human) Caroline Forbes
More than anyone else, Caroline's character arc changed drastically in the show, improving after she was turned into a vampire by cunning Katherine. That worked out for her in the end, because human Caroline was quite vapid and a bit of a mean girl, especially to her own friends.
She was competitive with Elena, who had just survived a major traumatic event, about boys, cheerleading, and life in general. Bonnie had to often keep her in check, but Caroline was pretty mean as a human, which was a quality that vanished with vampirism.
Katherine Pierce
If being unkind was a competition, Katerina Petrova would secure first place. Apart from being extremely conniving, she was also sharp as a razor and could tear people's self-esteem to shreds whenever she wanted. Elena was her usual target, and she loved saying horrid things about how bland and off-putting she was.
Katherine toyed with Damon repeatedly, as well as Trevor and Elijah. She did whatever she had to to survive, and somewhere along the way she became a twisted person.
Mary Louise And Nora Hildegard
This iconic couple was exciting to watch on screen, especially when they paired up to torture or disturb people together. With Caroline, they came up with t little schemes to mess with her and did so with Valerie as well.
It was obvious that Mary and Nora were two very similar beings who had found each other. They didn't think twice before terrorizing an entire college to get their sibling back from Damon, and being mean was a bit of a hobby for the two of them.
Kai Parker
The formidable Kai Parker was a villain with style, and his misdeeds were tempered with vile and loathsome behavior which he directed towards Bonnie, Damon, and his own coven. He was a product of his circumstances, but even that can't justify mass-killing your family.
He stabbed and double-crossed Bonnie, killed a pregnant Jo, put Elena in a permanent slumber, and helped Katherine when she was queen of hell. Several people around Kai suffered for no real reason, like his cab driver when he escaped the prison world. He was a true villain.
Isobel Flemming
Elena's mother and Alaric's ex-wife was really unfriendly and callous, especially to the two people who were actually related to her. She blackmailed and tried to capture Elena, and spoke unkindly to Alaric who only wanted an explanation.
She was friends with Katherine, which reflected on her character pretty badly anyway. Until the very end, she didn't act like a mother to Elena but used her as a pawn in Katherine's games. Isobel wasn't a good human nor was she a good vampire.
Sybil
The Siren was quite irritating to many fans, but her interference in Damon and Enzo's memories really made her look like a mean girl. She viciously changed their memories, made them attack their lady loves, and made them carry out horrific deeds for her.
Sybil made the Salvatores kill their last living relative, and even betrayed her own sister to Cade to keep her powers. Sybil was cunning and spiteful, which made her instantly hated.
Bill Forbes
Bill Forbes, like many other of the Founder's Council, was prejudiced against the supernatural. He was very extremist in his views about them, but his hateful and baser side came forth when he treated his own daughter with unkindness when she became a vampire.
Bill tortured her and tried to condition her to control her thirst in the worst ways possible, which really showcased how far gone he was. Still, Caroline stayed devoted to him until the end.