It happened in advanced potions class. Slughorn had assigned new desk partners this year, and I was paired with fucking Lavender Brown of all people. Seriously. How that ditz ever managed to get into this class is beyond me.
Anyway, we were brewing (or ruining, in the case of my desk partner) Pepperup Potion. Brown, as always, kept up a constant, inane chatter over idiotic things such as clothes and whatever bullshit Witch Weekly had said about the Hobgoblins reforming with all of their original members, which is ridiculous because everyone knows the drummer, who was the only member who was actually any good, died two years ago.
Then she started going on about how hot Weasley was and how he'd never notice her and blah blah blah, and I finally snapped. I cast a stasis charm over my potion (couldn't have it spoil, now, could we?) and turned to face her.
"I swear to Merlin, Brown, if you don't bloody shut up I'm going to carve out your eyes with a plastic spoon!" I shouted.
The room was deathly silent.
Brown started sniffling. Oh, please, dear Merlin, tell me the bitch isn't really going to start crying.
No such luck. She burst into loud, wailing sobs and ran from the room.
"Miss Turpin," Slughorn said, "I'm afraid I'm going to have to take thirty points from Ravenclaw and assign you a detention for Thursday evening."
"Yes, sir," I mumbled, then turned back to my potion. Fuck. I lost my temper and now I have a bloody detention for Thursday night, and we have a Transfiguration test Friday morning!
'Oh, shit,' I realized, almost groaning aloud. 'Julie, Morag, and Quintus are never going to let me live this down!' I turned to look at Julie and Quintus at a table behind me in the row over, and sure enough, they're both laughing at me.
'Nope,' I thought, 'I'm never going to live this one down.'