[She won't thank his compliment. That's a sign of her own arrogance, but also an inevitable consequence of her upbringing. She wasn't raised to receive praise with humility. She turns her head, restores eye contact; makes things as they were before.]

You resent being treated and spoken to like a child.

[An obvious fact, but it's unusual for her to acknowledge someone else's feelings like this. It's especially rare that she makes an effort to discuss them, or to change her own behavior accordingly.

Barty isn't wrong about himself, or anyway she doesn't think he is. It's a fine and correct thing he's said out loud. He shouldn't be discouraged by the fact that her reply is somewhat contrary.]

What is ever enough for him?

[That's not bitterness, it's reverence. If she could, she'd hand her master the world, then ask — the very next moment — what else he wants.]

How much more does he deserve than his loyal servants can ever provide?

[Likewise, albeit for entirely different reasons, nothing is enough for her. Nothing she can ever hope to have. She's unmanageable, impossible. Without meaning to, she'd make anyone miserable who sought her approval. Narcissa's only immune because she earned her eldest sister's affection years ago, when it was more readily given.

They are permitted to make their own assessments of each other, distinct from their Lord's opinion — provided, of course, that their Lord's opinion is the one they act upon. His judgments are less fallible. Or infallible, more likely.]