So after season 2 of The Vampire Diaries I think, as I think many agree with, the series went downhill quite a bit. Season 3, especially towards the middle, was a mere shadow of The Vampire Diaries' former self and season 4 I think was by far the worst season.
So taking on this mindset in this blog entry I want to put forth what I think is the biggest sin The Vampire Diaries has committed against its own story and lore since season 2. I'd also be rather curious to hear what everybody else thought were the series' biggest sins, so if you would all be so kind as to leave a comment on the matter I would appreciate that. Anyway, my personal winner is...
The Deaths of Finn & Kol
The way Finn and Kol were killed off in seasons 3 and 4 of The Vampire Diaries respectively is in my opinion the most horrendous moment in the series' run in regards to ignoring its own established lore and continuity.
Despite both of them being originals, and Finn even being in the company of the 900 year old Sage, they were both defeated in mere minutes. While Klaus and Elijah have been seen fighting off armies of vampires and throwing younger vampires like Damon and Stefan aside without trying, both Kol and Finn were killed off by humans and baby vampires.
Finn was killed by Stefan, Elena and Matt (the latter two both humans) without any of them ever really even getting hurt. Now, unlike Kol what happened to Finn was a surprise attack. So there's at least a tiny bit more plausibility there. But that being said, originals are supposed to be able to react and move extremely quickly and be quite resistant to regular wooden projectiles, as we see when we first encounter Elijah and Stefan's wooden projectiles don't seem to even slow him down much. We even see Stefan catch a wooden projectile Alaric fires at him in season 1 and once in season 2 when one of the wolves fires a wooden projectile at him. Katherine too catches a wooden projectile, more than once, in her fight with Damon and Stefan in Masquerade. Despite this Matt and Elena have enough time to open the door, shoot FInn with a regular wooden projectile (while he's staring at them) and then Matt has enough time to walk up to him and drive a stake into his heart without Finn being able to do anything about this. By all reason the moment Stefan tried to stake Finn, Sage should've ripped his heart out, Finn should've caught the wooden projectile and killed Matt or Elena with it. Despite the "surprise" element to it, it wasn't nearly surprising enough to not give either Sage or Finn enough time to attack without doing some seriously implausible things.
Speaking of implausible things, Kol's death is an even worse offender. Because Kol has a rather long fight with Elena and Jeremy, facing both of them directly. At one point Elena even manages to hold Kol off for a little while with a cabinet and a wooden door. That's right, the newby vampire Elena holds off a 1000 year old original with a cabinet and a thin door. When Kol finally overcomes the fighting machine that is Elena, he tries to cut off Jeremy's arm but instead his arm is grabbed by Elena and she stabs him with the regular knife and this hurts him enough that he can be sprayed with vervain and staked. Looking at season 1 episode 4, Stefan threw a regular knife right into Damon's chest and Damon barely reacted at all. Even this 170 year old vampire didn't give a shit about being hit directly in the chest with a knife but we're supposed to believe that not only did Elena have sufficient strength to redirect the knife into Kol and hold it there but this hurt him enough that he couldn't fight back? It made absolutely no sense at all. But that's not even the worst part of it. Because aside from requiring a stretch in continuity that is completely beyond belief, it also requires a stretch in character that is completely beyond belief. Everyone, meaning Elena, Jeremy, Bonnie, Stefan, Damon, all of them, agree to kill Kol and thereby kill possibly thousands of vampires that they've never met. Yet the moral implications of these aren't adressed at all and it's all represented as being just a normal part of the plan. Now, that Bonnie and Jeremy would be willing to do this is at least plausible. Both of them have reasons why they hate vampires. Damon isn't the most moral guy, so I can buy that too. Stefan is less plausible, but I could at least concieve that he'd have a warped enough morality to do something like this (though it still needed to be adressed with him). But Elena? This is a person who's supposed to love several vampires and be a fairly moral person and yet she shows absolutely no distress at killing thousands of vampires just to reach a selfish goal. Either she changed a lot as a character, which should've been adressed, or it is completely inconsistent with the character they've been trying to portray for the last 4 seasons.
So this turned into more of a rant than I thought it would. Anyway, rant over. Your turn.