Hermione said, "Harry, how could you do that? Professor Quirrell's confidence problems won't get any better from you making fun of him. Would you make fun of Neville for stuttering?"
Neville said, "I-I won't still be st-stuttering when I'm that old.
"Of course not," said Harry. "Not to his face. Maybe a little in private." He clapped Neville on the shoulder. "But Neville actually stutters. Quirrell is just faking."
Hermione gave him a doubtful expression, so Harry said, "Don't tell me you haven't noticed. It's like he forgets for a moment, then stutters extra to make up for it. And it doesn't seem spontaneous like with Neville. Not convincing at all."
"Maybe he's bad at stuttering," said Hermione.
"Bad at stuttering?" said Ron.
Hermione said, "Think Harry. What's more likely? He's just pretending to have a stutter, embarrassing himself in front of all his students, or he's bad a stuttering? Imagine it, Harry. Not only does he stutter, which is horrible enough already, he can't even stutter right. He must be so embarrassed, and you made fun of him for it, to his face, in front of the whole class."
Neville said, "St-stuttering isn't that bad."
Hermione said, "Imagine if that were Neville, grown up."
Harry looked contrite. He bit his lip, glanced at his feet, and squeezed Neville's shoulder. "Sorry, mate."
You didn't make fun of m-me. You need to apologize to Professor Q-Quirrell."
Harry said, "Do I have to?"
"You have to," Hermione confirmed.
So Harry sighed, squared his shoulders, and marched back into the emptied classroom.
Professor Quirrel was at his desk, making notes in his lesson book, and Harry pulled up a seat before the desk, sat in it, and said, "Sir, I'm here to apologize. I was mocking you, a little. But I want you to understand that I wasn't making fun of you for stuttering. I was making fun of how you stutter. I'm sure you'll get better at it if you try."
Professor Quirrell set down his quill. "N-n-no worries, Potter. So long as you're s-sorry."
Harry nodded and patted Quirrell's hand.
Quirrell hissed and said, "Potter, I'll thank you kindly not to touch me."
"Sorry."
Quirrell pulled that hand into his lap, beneath the desk. It had a large, raised red welt where Harry had touched it, as if he'd played with fire and done it wrong.
Harry said, "I'm sure once you've improved your stuttering, you'll be a better teacher, and maybe you'll even be able to get a better job if you want."
Quirrell said, "Being a Hogwarts Professor is a prestigious position."
"Really? My Uncle said that school teachers don't-"
Quirrell said, "Voldemort himself applied for this position."
"Really? That's weird. He didn't get it, so what, he became a Dark Lord instead? Was that his fallback plan? Like, 'Oh, I'll try to make it as a teacher, but if that doesn't work, I'll conquer Britain?' Probably would've been a horrible teacher, too. Worse than Snape."