She slept through History of Magic.
She was a bit of an insomniatic, often exchanging sleep for Quidditch or mischief. Late night was the only time she ever had motivation to do homework either, as it often took that last minute stress to force her to even make the attempt. So after a night of attempting her make-up Potions essay, two Quidditch practices (because she was a maniac), and the promise of a late night argument with Lestrange was enough to convince her she deserved the nap. Besides, it wasn't like she would learn anything by being awake in History of Magic.
So she slept through History of Magic. And apparently there was a quiz. So she had a long weekend ahead of her of doing the homework she had not planned on doing. So it goes.
She showered the sweat from practice off and scarfed down dinner before slipping outside once more. Most of the students were heading in and soon the Caretaker would begin a sweep to make sure everyone was inside. She was supposed to meet Matt at the pitch to finally iron out the details of this little club they were warring over, but he had some late night commitment that meant she had time to kill.
She reached the Quidditch locker rooms and decided to jump on one of the practice brooms, her own locked upstairs in her room. She stayed low to the ground, wanting to stay hidden from any wandering staff, and kept it loose and slow, not looking to wear herself out in case her conversation with Matt devolved into blows once more.
It struck her, as she did laps around the pitch, that she was not someone people hung out with - at least, not on purpose. She couldn’t remember the last time she had made a plan with someone that wasn’t Quidditch practice. Even among people who would hazard calling her a friend (which was honestly asking a lot of the word) there wasn't much of the "see you after class" or "are you free Sunday?". More often that not, her socializations were unplanned, spontaneous, and often resulted in trouble. She pulled people into random adventures, often running into the library to ask for help with a prank, or mentioning after class, “Come on, the elves made cupcakes, let’s go eat them all right now.”
So this, meeting up with someone, even if it was for "business"... it was different.
Enough introspection.
So what's the point of finding calm, when calm to me is unsettling?
She did a barrel roll.
Rock on.
by 
