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 E8 "The Mysterious Mare Do Well"
Accidental Aesop: The episode's events easily support a decent aesop about acting responsibly in a crisis - Rainbow repeatedly put lives in danger by putting her showboating before doing anything to help, which Mare-Do-Well avoided. Unfortunately, the dialogue/the episode's inability to have Dash learn the lesson herself really don't support it, hence a lot of the complaints.
Accidental Innuendo: When Rainbow Dash pulls in Applejack for a photo opportunity, the positioning of the mouths and Applejack's reaction afterwards suggests something a bit more than being pulled into shot, which the fandom has noticed.
Alternate Character Interpretation/Broken Base: Even to this day, fans are bitterly divided over loving this episode or hating it. And pretty much all of it revolving how the actions of Rainbow Dash and the Mane Six are interpreted.
Mare-Do-Well (who is secretly five of the Mane Six) was either showing Rainbow Dash what a real hero was supposed to be like in the hopes of making her change her ways, saving ponies that Rainbow Dash would have been unable to save on her own with the disguise as a way of showing her humility, or made a piss poor attempt at teaching Dash anything, instead presenting her with an unbeatable rival, along with egging her on to dangerous and embarrassing actions with the disguise as just a cowardly and dishonest way of hiding from Dash.
Rainbow Dash was either doing good deeds all over Ponyville, acting as a real hero, and basking in much-deserved praise from the citizens then driven to despair and abandoned by even her most loyal fans because she came across as looking pathetic compared to Mare-Do-Well, or was bragging way too much to the point that it was endangering other ponies and was too stupid to pick up on the lesson that Mare-Do-Well was trying to teach her until she had it spelled out to her at the end of the episode.
Dash's friends were either having some good-natured fun among themselves and dropping hints to Dash that she would be happier and more successful if she just improved her attitude, or were cruelly mocking Dash and her misfortunes while praising Mare-Do-Well (i.e. themselves), completely and fully aware of how Dash would react.
When Dash confronted Mare Do Well, she then ran away. Either she was luring Dash away from the crowd so that the Mane Six could talk to her in private and not humiliate herself anymore, or was genuinely trying to get away from Dash so that she would not be humiliated herself.
Clueless Aesop: Contributing to the Broken Base, it's been repeatedly pointed out that the message of humility would certainly have been stronger if the scene in Sugarcube Corner had Twilight, Rarity and Applejack praising each other's contributions to Mare-Do-Well rather than their own (fixing the dam, her outfit and her overall humility respectively). You're not being humble when you're talking about how humble you are.
This is also doubly weird, as the main cast have done far greater deeds than Rainbow Dash did in this episode, such as, say, saving Equestria. Twice.
This edited version even omits the entire Sugarcube Corner scene so as to make the Mane 5's actions seem even less questionable.
Internet Backdraft: Mentioning this episode can lead to year-long flame wars, even on this very wiki.
Jerkass Woobie: Rainbow Dash upon savoring her popularity becomes an egotistical ass and vents a lot of spite towards Mare Do-Well for taking it away. As her attempts to gain credibility get more and more pathetic however, you can't help but feel even a little bit sorry for her. After all, she's justtrying to be a hero.
Never Live It Down: This was the first episode written by Merriwether Williams, who still hasn't escaped a reputation as the show's worst writer despite several of her later episodes being better received. See especially the episode "Bats," which was pretty much universally loved...until it was revealed the writing credit was a mistake, and it was actually Williams.
The Scrappy: Depending on who you ask, this status is handed generously to either Rainbow Dash or the rest of the Mane Cast.
Scapegoat Creator: The Broken Base nature of the episode immediately elevated the new writer Merriwether Williams to the level of The Scrappy of the MLP writers, while she has since written a several more episodes that have had better reception, she still has a sizable hatedom.