Page 485 — Heart to Heart
As far as "stuff I'd like to see more of in official content" goes, I wouldn't mind seeing more personal interactions between Celestia and the rest of the Mane Six. Twilight usually gets all the attention, and there isn't much of a defined attitude or relationship between Celestia and the rest, other than "they're Twilight's friends." It makes sense why it's that way (and why the show doesn't really have time to focus on that), but it's just one of those things.
Transcript:Princess Celestia: Hello, Rarity. I don’t think we’ve had a chance to speak… one-on-one.
Rarity: It’s an honor, Princess.
Princess Celestia: What brings you to Canterlot?
Rarity: Oh, you know… Mostly business, but I can’t pass up the opportunity to take in the city, the ponies, the glamour…
Princess Celestia: Is that so? In this day and age, the glamour often hides something sinister.
Rarity: I’m well aware. But I am not deterred. Quite the opposite, in fact!
Princess Celestia: Yes, you do have an appetite for danger, don’t you? A dragon, the Diamond Dogs, and now the Canterlot elite.
Rarity: …Am I in trouble, Princess?
Princess Celestia: No. Ultimately, no. But I have a few things I want to say.
Rarity: Ah. I think I’m going to panic anyway…!
Princess Celestia: I would prefer that you didn’t.