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 E13 "Hearth's Warming Eve"
In addition to their general hostility toward the other pony races, each leader has a flaw that represents a common criticism against government: overly aggressive and war-mongering (Commander Hurricane/Rainbow Dash), aloof, pampered, and out-of-touch with the people (Princess Platinum/Rarity), and incompetent or even idiotic (Chancellor Puddinghead/Pinkie Pie). Is this a simple holiday myth about friendship, or a multifaceted fable about how to maintain harmony, both among individuals and in a greater community?
Another theory is that the characters were the Ancestors of the Mane Six. One doesn't actually need to be familiar with MS Paint Adventures to understand what that means but it might help.
It might have been made as a Lighter and Softer version of the real events as well, so they wouldn't have to show ponies starving and dying.
Also note parallel founding myths in the real world. It doesn't help that the word wendigo, whatever it means in Equestria, in our world describes a being found in certain indigenous North American stories.
Were the windigos evil spirits intentionally causing the ponies suffering and grief or non-sentient beasts who were merely feeding and their natural way of survival made them a dangerous threat?
A couple of fans have interpreted the windigos as good spirits who were punishing the ponies for fostering such hatred.
Awesome Music + Ear Worm: That song at the end was so sweet and heartwarming; how can one not hum along to it.
The Equestrian flag the three tribes decide on at the end looks almost but not quite like Celestia and Luna but could as easily be a Yin-Yang representing the new balance and harmony between the races.
Les Yay: Compared to the other groups, Platinum and Clover seem rather...close.
The Les Yay might stem from the fact that they are both played by mares playing to the script, but for all we know, Clover was male originally. In fact, all of them except Princess Platinum could have been male (the most likely cases being Commander Hurricane and Smart Cookie, which can be assumed from the fact that AJ keeps her long hair tucked in her costume for the most part except an animation error, which is the poor-mans way of making a long-haired actor/actress appear to have short hair. The commander is addressed as "sir" and is only referred to as "her" once, which may have been a mistake of Fluttershy's).
Narm: A possibly intentional case of it (seeing as how the characters were acting in a play) but the cave scene was filled with this.
Narm Charm: It still manages to grip at a great deal of hearts.
Nightmare Fuel: Even though they're portraying other characters, it's still disconcerting to watch as beloved members of the Mane Six freeze solid with their faces contorted with hatred.
When the leaders of the three tribes and their assistants are making up, there are small snippets that are very reminiscent of "Greensleeves" playing.
And another one of the jingles (used primarily for Princess Platinum) is extremely reminiscent of the opening tune of nothing less than Exodus.
Uncanny Valley: Pinkie shows another one of those weird smiles similar to Rainbow Dash and Fluttershy's in "May the Best Pet Win!", but mileage varies, especially when one considers her 'about to be brilliant' face adorable.
The windigos also inhabit the valley. Suddenly cutting from the show's usual style to relatively realistic horses with Blank White Eyes and no back legs is quite jarring.