I wanted to understand your personal reasons for shipping Rarijack?

As in, what about their personality and dynamic makes them so much fun together? What about them sells the idea of them loving each other romantically and not just platonically?

because opposites attract. They are perfect

I could and have written walls of text for these two on why they are perfect for each other. So I won't do that here, again. I will say that Rarity is often placed as a Damsel in Distress and Applejack is usually the hero/prince charming, the role flips sometimes but the two compliment each other well. They also aren't super excited about certain aspects of each other, making for drama and development as a couple and individuals, hurdles for them to get over, which makes for great story.

6775806
I've always liked them as a study in contrasts and compromises. Neither one can compromise easily, but they accept it wholeheartedly when they see the light. They're a dramatic couple, and given the right circumstances and nudges from others, could grow to be a strong couple, happy with the compromises they've made to make their lives fit together in a way that makes sense to them, even if it doesn't look much like what they might have imagined at first blush.

It's that budding dynamic, and the building of the relationship into more than friends that interests me as a challenge (not that I've written anything with them, or read much about them) but it's something that if done well, could be a very compelling romance and journey on through life together.

I personally like the idea of a romance between the elegant, fancy person with the hard working, field cropping farmer.

Truthfully, the answer can be as simple as "opposites attract" because that's just a dynamic that people absolutely adore. Ex: a rustic farmer with a sophisticated big city goer, a loud dare devil with a quiet animal lover, a brash and fun loving dj with a refined and serious member of a high society orchestra. These are just a few of many examples, but it's their differences and how they can embrace and appreciate each others differences that make them capable of loving each other either at a platonic level or as more.

For Applejack and Rarity specifically it's how Applejack doesn't mind getting dirty, and Rarity enjoys staying clean, but they're both tireless in their life's work and are more than willing to step out of their respective comfort zones to help the other. How Applejack's blunt and honest nature can help Rarity see past her own dreams and infatuations, but Rarity's own grip on society and compassion for others can help her to show Applejack when being honest can hurt more than help. If I'm being completely honest though my main reason for shipping them is just how they always seem to rely on each other, appreciate each other, and ultimately appear closer than most of the other main six (seven now, maybe eight with Spike? Idk anymore) even past childhood friends like Rainbow Dash and Fluttershy. A personal reason though is that I feel like Rarity is always looking for her "prince charming" a stallion/man who's charming, kind, honest, humble, strong, reliable, and will support and love her through anything; and look past the stallion/man part and those characteristics fit Applejack perfectly. So I usually like to think that Applejack is the "prince charming" that Rarity's been looking for, she's just looking for him in the wrong place and hasn't realized it yet.

Hope that answers your curiosity. I honestly suck at describing things and tend to ramble so this may just be repetitive gibberish to you.

6776080
It does. Thank you!

Also, they are both workaholics.