Actor Allusion: Her English dubber is slated to play Belle in Guillermo Del Toro's Beauty and the Beast adaptation, so Subaru had good reason to fear she'd get the part in the drama department's production of the Disney version. She doesn't.
Also, her line in episode 15 when she explodes upon seeing Ichigo act friendly toward Cherri after being reunited with her after all these years: "YOU—COMPLETE—ASS—ICHIGO—TANAKA! YOU—CRAWL—BACK—TO YOUR—DAUGHTER—AFTER—YEARS—AND—YEARS—oh, where's my Chimer?"
When she gets snail mail from Slash in episode 16, she hesitates before opening it, fearing it's been laced with anthrax. Airi slaps her for the effort, and Subaru counters, "What? I was only referencing a book I read once."
You'd think she'd be fully satisfied when the guy that recommended her to play Tiana in the first place wound up playing Haruhi Suzumiya in a later production; however, since he and Haruhi are both perverts Subaru is actually unsure on the matter at hand.
Precision F-Strike: A frequent offender, having cursed in several episodes (including a near-miss with "son of a bitch" in episode 23).
Shotgun Dance: Does an impromptu tap dance in the first movie to avoid sinking into quicksand that she had accidentally stumbled into while searching for traces of sand in a snow-covered desert resort.
Subaru: I don't think that was normal sand. Airi: What was it, sister? [beat] Subaru: It's quicksand.
Status Quo Is God: Every time she makes a Face-Heel Turn, it's because she'd been brainwashed, rinsed, and dried, and she returns to normal when the Cures exorcise her. Also, every time she's put in a situation that could put her in a skirt (e.g. being cast as Tiana in The Princess and the Frog or infiltrating a girls' school to protect the Chief's daughter), something will always, without exception, come up to prevent that from happening (e.g. being demoted to backstage duty, or it turns out the girls' school in question has a uniform that does not incorporate a skirt).
Stock British Phrases: Utilizes them sometimes; in terms of being family friendly, this includes her infrequent usage of the word "ass" (the British consider "arse" to be more vulgar, whereas in America it's the other way around).