Despite knowing his potion was textbook perfect, Harry still felt a familiar clench of anxiety in his gut when Snape lingered at their station, his black eyes staring intently at each of their cauldrons in turn. There was a moment when Harry was convinced the potions professor was about to pick fault for the sake of it, before he turned away without comment, and Harry let out his held breath. He peered discreetly over his shoulder at Ron and Hermione behind him, and found Hermione’s own perfect potion shimmering away, and even Ron had managed something that looked vaguely like the right potion.