I love Naz's mildly annoyed expression. It's as if this happens to her on a regular basis and she's come to regard it as just another of Shou's inconvenient habits.
Part of why I love Utopia's work is because he's very good at expressiveness. Like say, Reimu's annoyed glare in the Yukari pic. Or Flandre's and Meiling's surprise in that pic, too.