While Celestia is constantly being bugged by Discord, I'd presume she'd have some immunity to his nonsense. Luna, on the other hoof, wouldn't see Discord as much just because he prefers irritating Celestia (I presume), but I'd say she has much less tolerance for him.
Dunno, food for thought.
Three French Maids
Two Tortoise Shells
And a Whole Season Of My Little Pony
Discord- Why what is it, my pretty wittle maid.
Celestia- the only reason why me and my sister did not kill you is because it would have destroyed too much of equistria................ slowly i am beginning not to give a fuck about property damage.
Celestia: "I am a princess!"
Discord: "All the more reason you shouldn't have such bad posture!"
Fluttershy: "Discord said I looked cute as a maid!" *in her happy place*
This was easily my favorite panel of the collaboration. I said the same thing where the whole thing was posted, but I felt I needed to come here and repeat it.
Discord looks like he's having a blast, as usual, and Celestia looks wonderfully bitter about it.
You are a genius.