Snape sat at his desk, waiting impatiently for his troublesome student to arrive for detention. He looked at the clock, gritting his teeth in annoyance.

Finally he heard the sound of footsteps running down the hall, coming to an abrupt stop just outside of his classroom. There was a loud knock on the door.

"Enter" Snape growled, his expression hardening as you walked through the door. "Once again, you have wasted my time by being late for detention. Explain yourself," he demanded, his tone brooking no argument.