I'm not totally sure why exactly, but I really love this. The look on her face, her posture, it's just so expressive.
Plus the glasses are adorable. It tells a story, clearly they've BEEN doing something and she's about to get up and do other things as she's put her underwear and glasses back on- he is trying to convince her not to, and she's trying to convince herself not to let him, but knows it's a losing battle.