Hermione discovers why Griffindor didn't win the House Cup for years.

"So, I was scouring the records documenting all the House Point deductions ever the years..." Hermione said. "That does sound like something you'd do." Ron said, rolling his eyes. "...and I think I now know why Griffindor didn't win the House Cup for so long." Hermione finished the sentence, ignoring Ron.

"Yeah? Well, I can tell you right now it's Snape." Harry said. "He takes points from us for any arbitrary reason he can think of!"

"Well, professor Snape certainly doesn't help..." Hermione said. "...but he's not the one that takes away most of our points. It's actually professor McGonagall."

Harry and Ron looked at each other in confusion before Hermione started explaining. "She takes more points than the other professors from all houses, but she's particularly strict with us. Significantly more than the other houses. On average, she takes twice as many points from Griffindor as professor Snape does."