These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: MLP: Friendship Is Magic S2 E22 "Hurricane Fluttershy"
Accidental Aesop: From Dash's failed efforts to break the record; just because you can't be as good as you try, be comfortable with being good enough.
Alternate Aesop Interpretation: Even years after the fact, Fluttershy is psychologically damaged by childhood bullying and teasing. Thus this could certainly be seen as a message about how badly that kind of thing can hurt someone.
Big Lipped Alligator Moment: The muscular pegasus appearing for a few seconds and screaming YEAH! Never established in previous episodes, has a Non-Standard Character Design, and barely acknowledged after an appearance. Retroactively Averted with the Season 3 episode, "Wonderbolt Academy", where he shows up again as a Wonderbolt cadet.
Ensemble Dark Horse: The massively-muscled pegasus with the tiny wings, who had fanart within about ten seconds of the preview clip airing. (Subsequently named either Snowflake or Roid Rage by the fandom)
Flitter, Cloudchaser, Thunderlane, Rumble, and Blossomforth have developed a following as well. The former two especially, with their distinctive designs (Flitter's pink bow and Cloudchaser's Anime Hair mane) likely contributing to that.
Getting Back on Your Hooves had a Circle of Shame flashback to flight school disturbingly similar to Fluttershy's in this episode, only with Rainbow Dash, despite the chapter being posted about two weeks before the episode aired.
Les Yay: When Rainbow Dash is first trying to get Fluttershy confident in her cottage, this exchange occurs, leading to jokes about Fluttershy confirming an alternative choice of lifestyle and Rainbow Dash being overjoyed to hear it.
Fluttershy: I'll do it. Rainbow Dash: You will!? Fluttershy: I will. Rainbow Dash: You're game!? note as part of the joke this is deliberately misheard as "you're gay!?" Fluttershy: I'm game. Rainbow Dash grabs Fluttershy and flies through the air holding her. Rainbow Dash: ALRIGHT!
There's also some heartwarming moments between the two like Rainbow Dash's "But I need you!" and Twilight's "Do it for Rainbow Dash!"
Never Live It Down: Surprisingly averted in the case of Cloudchaser and Flitter. The two are clearly laughing at Fluttershy during the first time she measures her wing power which in turn is what sets off her panic attack. Despite this and how the viewers normally react when a character treats Fluttershy in some sort of negative way (just look at Gilda) the two still have a bit of a following. Then again, them also congratulating her at the end of the episode may have made up for it.
Fluttershy was bullied in school, and being shoved off a cloud by her teacher.
Rainbow Dash too for having to watch her best friend get bullied back in Flight Camp and fail at making the tornado in front of her idol, Spitfire. It's hard not to applaud her and Fluttershy when the two finally make the tornado.