Learning that fans hated Applejack and called her "boring" is crazyyy to me because I genuinely, unironically believe AJ's the most complex character in the main six.
Backstory-wise, she was born into a family of famers/blue collar workers who helped found the town she lives in. She grew up a habitual liar until she had the bad habit traumatized outta her. She lost both her parents and was orphaned at a young age, having to step up as her baby sister's mother figure. She's the only person in the main gang who's experienced this level of loss and grief (A Royal Problem reveals that AJ dreams about memories of being held by her parents as a baby). She moved to Manhattan to live with her wealthy family members, only to realize she'll never fit in or be accepted, even amongst her own family. The earlier seasons imply she and her family had money problems too (In The Ticket Master, AJ wants to go to the gala to earn money to buy new farm equipment and afford hip surgery for her grandma).
Personality-wise, she's a total people-pleaser/steamroller (with an occasional savior complex) who places her self worth on her independence and usefulness for other people, causing her to become a complete workaholic. In Applebuck Season, AJ stops taking care of herself because of her obsessive responsibilities for others and becomes completely dysfunctional. In Apple Family Reunion, AJ has a tearful breakdown because in she thinks she dishonored her family and tarnished her reputation as a potential leader –– an expectation and anxiety that's directly tied to her deceased parents, as shown in the episode's ending scene. In The Last Roundup, AJ abandons her family and friends out of shame because believes she failed them by not earning 1st place in a rodeo competition. She completely spirals emotionally when she isn't able to fulfill her duties toward others. Her need to be the best manifests in intense pride and competitiveness when others challenge her. And when her pride's broken, she cowers and physically hides herself.
Moreover, it's strongly implied that AJ has a deep-seated anger. The comics explore her ranting outbursts more. EQG also obviously has AJ yelling at and insulting Rarity in a jealous fit just to hurt her feelings (with a line that I could write a whole dissection on). And I'm certain I read in a post somewhere that in a Gameloft event, AJ's negative traits are listed as anger.
Subtextually, a lot of these flaws and anxieties can be (retroactively) linked to her parents' death, forcing her to grow up too quickly to become the adult/caregiver of the family (especially after her big brother becomes semiverbal). Notice how throughout the series, she's constantly acting as the "mom friend" of the group (despite everything, she manages to be the most emotionally mature of the bunch). Notice how AJ'll switch to a quieter, calmer tone when her friends are panicking and use soothing prompts and questions to talk them through their emotions/problems; something she'd definitely pick up while raising a child. Same with her stoicism and reluctance at crying or releasing emotions (something Pinkie explicitly points out). She also had a childhood relationship with Rara (which, if you were to give a queer reading, could easy be interpreted as her first 'aha' crush), who eventually left her life. (Interestingly enough, AJ also has an angry outburst with Rara for the same exact reasons as with EQG Rarity; jealous, upset that someone else is using and changing her). It's not hard to imagine an AJ with separation anxiety stemming from her mother and childhood friend/crush leaving. I'm also not above reading into AJ's relationship with her little sister (Y'all ever think about how AB never got to know her parents, even though she shares her father's colors and her mother's curly hair?).
AJ's stubbornness is a symptom of growing up too quickly as well. Who else to play with your baby sister when your brother goes nonverbal (not to discount Big Mac's role in raising AB)? Who else to wake up in the middle of the night to care for your crying baby sister when your grandma needs her rest? When you need to be 100% all the time for your family, you tend to become hard-stuck with a sense of moral superiority. You know what's best because you have to be your best because if you're aren't your best, then everything'll inevitably fall apart and it'll be your fault. And if you don't know what's best –– if you've been wrong the whole time –– that means you haven't been your best, which means you've failed the people who rely on you, which means you can't fulfill your role in the family/society, which makes you worthless . We've seen time and time again how this compulsive need to be right for the sake of others becomes self-destructive (Apple Family Reunion, Sound of Silence, all competitions against RD). We've seen in The Last Roundup how, when no longer at her best, AJ would rather remove herself from her community than confront them because she no longer feels of use to them.
But I guess it is kinda weird that AJ has "masculine" traits and isn't interested in men at all. It's totally justified that an aggressively straight, misogynistic male fandom would characterize her as a "boring background character." /s
At the time of writing this, it's 4:46AM.
