Harry honestly did try to pay attention to his lesson, but Snape's handwriting was too blurry. He didn't want to use a magnifying charm and he didn't want to bring the parchment close to his face either, as both of those things would draw attention. But he had to learn the lesson, and it was bad attention from Snape or bad attention from Snape. He sighed, and squinted at the paper before grudgingly bringing it closer to his face.
"I can assure you, Mr. Potter," Snape's voice came from behind him, making him jump a bit in his seat. The man smirked, but continued in a bored drawl, "if I were to poison you, I wouldn't put it on your parchment of all things."
The Slytherins snickered, and Harry's ears grew red. "Oh, uh, no, sir. I'm just trying to read the paper."
"I see," Snape said. "Not inhale it, as I previously thought?"
More laughter.
Harry slumped. "I can't see it, sir," he gritted out. "I never got prescription glasses."
"Ah," Snape said, and there was a flicker of surprise in his eyes. His wand came out into his hand so suddenly that Harry flinched. Snape looked almost approving, before he cast something and put the weapon away. "A simple vision charm, Mr. Potter. Do fix your glasses."
Harry looked all around, and he could swear that when he said, "Oh, that's the difference between these plants," he murmured to himself. Out of the corner of his eye, he swore he saw Snape smile.