What made main characters to be worthy to their Element?

I feel confused about why some of the main characters are representing one of the Elements. Not all of them, since Twilight fits the Element of Magic, Pinkie Pie fits the Element of Laughter and Fluttershy fits the element of Kindness. But...

AJ actually often struggles to be honest. And when she is honest, it is nothing special, as a lot of ponies are honest just as much as she is. So... how she is more honest than others and deserves to represent the Element of Honesty? The show did show that she deserved that after... not telling Twilight that someone will catch her? She wasn't lying, but she wasn't 100% honest/clear with her words. Strange for me.

RD is the same. She is the pony who is the most focused on herself, which is a strange choice for the Element of Loyalty. Her choices are often focused on her own goal and only after it is done she is like 'darn, that wasn't loyal at all'. Also, in the show, she became worthy of the Element of Loyalty after... not joining a group of total strangers that appeared out of nowhere in the middle of the dark forest? It's logical, not loyal...

It might be because of me failing to notice it, but I'm not often seeing Rarity being generous in her everyday actions, though it can be caused by her being a business owner. That generous trait of hers is only noticeable in episodes that are focused mainly on Rarity. So I dunno, she does seem to be more generous than your average pony. Cutting off her tail to make a heavy impression that she is super generous felt a bit off... and meaningless, as her tail was restored shortly after.

I'm probably expecting too much logic from a kid show, but well, I'm curious about what others think about it.