So earnest. So dedicated. So annoyingly naive for SO LONG! I'm actually relatively fond of Yuna: she has such a difficult job to do, and such strength in doing it. She's certainly not my favorite character, but she's so brave and determined throughout the game, and deserves kudos for it. I mean, this is a girl who would willingly sacrifice herself--her body, her soul, her happiness--for Spira, even at such a young age. To be willing to work to save your world no matter what the cost....That's dedication.
I also love her relationships with the aeons, particularly Valefor. The way she lovingly summons them...the heart-breaking way she releases them at the end of the game....You know these are more than spiritual entities; they're her friends. While some--like, say, Seymour--use aeons as a power trip, Yuna works with them for a better future. And she's so dang polite to them! You've gotta love good manners in a heroine, even if she's an annoying damsel in distress most of the time. -_-;;
"Lost your nerve?"
"No. Nothing scares me now."
"Braska would be proud."
Auron and Yuna seem bound together more out of duty and respect rather than genuine friendship. Auron promised Braska he'd look after Yuna and he does so, offering advice but trusting in Yuna's judgment, protecting her in every way he can. Yuna, for her part, shows great respect for Auron and his capabilities. Whenever she's lost or needs to make a major decision, Yuna comes to Auron. She looks to him for guidance and desperately wants his approval. They're polite and very aware of their positions, so their attitude toward each other sometimes comes across as cordially distant.
Only on a few rare occasions do we get to see what might have been between these two, if they'd had a chance to really know each other longer. Auron didn't have to tell Yuna how proud her father would be of her. He didn't have to let her make her own decisions about how to deal with Seymour. He even manages to tease her along with the others once or twice. Maybe Auron sees some of Braska in Yuna. Maybe he sees Yuna as the daughter he could have had, if things were different. And maybe Yuna sees Auron as the closest thing to a father she's ever really known.
So while on the surface their relationship seems mostly made out of duty, deep down there's the possibility for a much more familial aspect...especially given that Auron, along with Jecht and Braska, takes time out of his busy afterlife schedule to cheer Yuna, Rikku, and Paine on in the final battle of FFX-2.