Simon was still in the habit of classifying people based on his own world; while Cait Sidhe typically had more subtle signs of their feline nature in their humanoid forms, he can't help think of one when he sees Y'shtola. Certainly the association means he's not unfamiliar with the body language.
"It is," he commented. "Of all the travelers I've spoken to, many find common elements of their homes in this world, but none of us seem to find it exactly like our own worlds."
The Grand Masquerade
"It is," he commented. "Of all the travelers I've spoken to, many find common elements of their homes in this world, but none of us seem to find it exactly like our own worlds."