“Come on, when have my calculations ever been wrong?”
“Shut up, that was one time.”
“Yeah, but for you, that’s one time too many, Hermione… Plus that one time nearly got us all killed.”
“It wasn’t that bad!”
“Yes it was! You’re better at Potions than that, you should have known better! Any other time, you’re triple-checking the directions and quadruple-checking the ingredients, just to make sure you’re not off, but that one time you failed to do so, the potions lab nearly blew up!”
“It really wasn’t that bad…” Hermione said weakly.
“Yeah, it really was, ’Mione,” Ron chimed in.
“Oh thank you, Ronald, I really needed that,” Hermione huffed.
“Well, it’s true, and getting upset about it long after the fact isn’t doing any good,” Ron pointed out reasonably.
“Well, continuing to point out how badly I messed up isn’t doing you any good,” Hermione replied tartly.
“You’d better watch it, mate, you’ll be sleeping on the couch for the next month,” Harry warned his best friend with a grin.
“Wouldn’t be the first time,” Ron muttered.
“What was that, Ronald?”
“Nothing, dear, nothing at all,” Ron replied innocently, as Harry started laughing.