Prompt was Monday mornings.
Everybody hates Monday mornings. For once, Severus Snape was no exception. In fact, he hated mornings in general. He wasn't one to sleep much, but whenever he did manage it without too many nightmares, getting out of bed in the morning was even harder.
It was amusing to see someone else go through it, though. Harry Potter, the Boy Who Lived, hated Mondays even more fiercely than Severus did.
And Severus was not above using that information for his entertainment. Sometimes he purposely kept Harry awake and... occupied, well into Sunday nights, making him late for Monday morning double Potions.