There have been so many great episodes this season, so this was pretty difficult!
Castle Sweet Castle: This probably isn't going to be on most people's lists, but I really enjoyed it! The song was catchy, the character interactions and humour were great, and the ending was really sweet.
Tanks For the Memories: A great Rainbow Dash episode that explored her emotional side, which is something we don't get to see too often. I really felt for her, and the emotions of the episode seemed very genuine. The song was fantastic as well.
Rarity Investigates: This episode focused on my two favourite characters, which automatically made it awesome. I really liked the continuity and humour, and watching best pony being fabulous is always great.
Crusaders of the Lost Mark: I've always been a fan of the CMC, and I liked Diamond Tiara even before her redemption, so I was extremely excited for this episode. I expected to see another side to Damond Tiara, but in addition to that we got a complete reformation, another musical episode and the CMC finally getting their cutiemarks! Needless to say, it completely exceeded my expectations and is without a doubt my favourite episode of the season.
The Mane Attraction: I loved this episode. Rara was a great, interesting new character, and the story was really sweet. It was great to see an Applejack episode that didn't focus on her farm or family - while I love Applejack, the episodes that stray a bit from her usual theme always seem to be her strongest. Pinkie Pie's characterisation was spot on, and I loved the interactions between Applejack and Rarity. The Spectacle song was great, and I'm not going to lie - I completely jammed out to it. A fantastic way to finish the slice-of-life episodes for the season!