Have always loved Twilight Sparkle as a character, to me she is an interesting and often relatable character and 'My Little Pony: Friendship is Magic' more often than not did so well at fleshing her out. Although she was interesting from the get go, development-wise she has come on a long way. Most episodes where she is the primary focus do her justice, while still letting the rest of the characters shine, and are very good and more in their own right.
One of the best examples of all of this is Season 5's "Amending Fences". One of the best Twilight-centric episodes and as far as Season 5 episodes go it is definitely in the top 5 and perhaps even the top 3. Would go as far to say even that it is one of the show's best too. After being severely underwhelmed by "Princess Spike" and being mixed on "Party Pooped" it was great for the season and show to return to form. Namely for the character writing, interaction and its emotional impact, three main reasons as to what fans love about 'My Little Pony: Friendship is Magic' overall in the first place.
Twilight is brilliantly written here in one of her most important episodes character development-wise. She is true to character and written authoritatively and honestly, with her want to change the past being completely believable and genuine and shows how much she has matured since the show first started. Moon Dancer brings a lot of heart and poignancy to the story and her chemistry between her and Twilight is a big example of why 'My Little Pony: Friendship is Magic' excels so much with its character interaction.
Pinkie Pie brings some very amusing and well balanced humour that contrasts very well with the emotion that doesn't feel out of place at all. While Spike's role is not massive, he still serves a point and not in the background while being treated with respect as a character by the writers this time. The writing balances humour and pathos with adept ease, with the pathos being truly touching without being too sentimental.
"Amending Fence's" story is hugely absorbing and explores a very mature subject and theme with honesty and heartfelt poignancy. Also one that so many that want to rekindle friendship and learn from past mistakes, having been there myself, will relate to hugely without feeling manipulated into doing so. The ending is one of the most emotional scenes of the whole show and all the continuity makes sense and fits, nothing contradicted which is a danger with continuity when harkening back to previous episodes.
Furthermore, the animation is colourful and rich in detail and the music dynamic. Tara Strong and Kazumi Evans knock it out of the park with the vocals, Evans' delivery in the climax is the voice acting highlight.
Overall, brilliant, a Season 5 high point and what 'My Little Pony: Friendship is Magic' is all about. 10/10