The trio watched the Potion Master explain the dangers of Calming Draughts. How the user could become addicted it was brewed wrong, and why they - especially the fifth and seventh years - should not self-medicate. Since it was OWL year, Severus had little hope that his words were heeded, but the potion was part of his curriculum. The "golden" trio observed while going through their preparations. No matter if they were paired with each other or with other students, the boys usually let Hermione take the lead, so their potions came out perfect every time. That gave Ron and Harry time to watch the other students and - more importantly - their professor.