I didn't find you worth the effort to come up with something more creative. [It's not like making fun of her sunglasses is unusual.]

Because my highly important research needs books, and libraries are quiet public spaces. Surely someone as manners-conscious as you knows that.

[She crosses her arms, raising an eyebrow behind her sunglasses.] What were you muttering about anyway? Singing the alphabet song under your breath to help you find something?