Season 1:
I will have to say Founder's Day as well. It was just a great episode, overall. I had never read or heard of the books at this time, so the Tyler thing was like a WTF moment for me. Anna dying, I didn't expect that. The mayor as well. Katherine. It was just so many surprises, gasps, and oh my moments. I loved it.
Season 2:
The Last Dance, is probably my overall favorite of the series so far. It was so touching and so Bonnie-centric, I loved it. The Bamon dance and scenes :heart:This season is my favorite, so far, so I have a couple honorable mentions. Plan B, I liked Mason and hate he died so soon on the show. Bamon banter was cute,Caroline and Bonnie became friends again, and Elena was out of the loop. She was so annoying this episode though. Also, Masquerade, again Elena was out of the loop. It was a lot happening, Tyler became a werewolf, Bonnie met a relative, they were all working together and I love when they do that.
Season 3:
This is harder for me because season 3 is my least favorite season. I would probably say The Reckoning. It was exciting. Stefan going full on Ripper, but trying to fight it for Elena's sake. Bonnie rushing to saving the day (as usual) Tyler becoming a hybrid. I like most episodes that have all of the main cast in them, and this one did just that.