Rainbow Dash was my favorite pony the first time I watched the show, and don't be mad at me Rainbow Dash fans, I'm not much for her anymore. Twilight became my favorite, next Applejack, Pinkie Pie, Fluttershy, Rarity, and finally Rainbow Dash. About AJ, she seems to be Twilight's most solid friend. I didn't like Applejack that much, but then I found out what an amazing pony she really is. Applejack is special to Twilight, Twilight cured her during Discord's "reign" first, and only showed her flashbacks. And I love Twilight a lot, so I trust her judgement. The cool thing about Applejack is that she is an earth pony, so she is very modest and down to earth. She has learned to be very grateful for what she has (notice she didn't sulk when Twilight became an alicorn, I can understand why her other friends didn't sulk because they are pegasi and unicorns) I know Pinkie Pie didn't sulk either, but who has ever seen Pinkie sad? (except for when it is her personal stuff with friends with different things like abandonment, ignoring, etc.)