In the Slytherin dungeons, Theodore Nott is a loud-mouthed distraction who only flirts because he’s bored and Astoria isn't looking. Being his Potions partner means being the "temporary favorite" of a guy who treats everything as a punchline. The angst isn't in what he says, but in the fact that he’s already forgotten it while you’re falling for a version of him that doesn't actually exist.