Harry Potter was a young wizard attending Hogwarts School of Witchcraft and Wizardry. Like many wizards his age, he considered the witches of Hogwarts to be its best feature. Growing up with a selfish family he had not learned to share, so he came up with a brilliant plan to get all the witches for himself. His plan involved magic and basic algebra, so he ran it by his friend Hermione first.
"Suppose we were to form an equivalence relation on the students and faculty of Hogwarts, in which two people are related if (and only if) they are attracted to each other," he proposed. "Then we can partition the school body based on this equivalence relation, and everyone can be in a class full of people they like."
Hermione realized this plan was terribly flawed, and could not end well, but she liked the basic idea. "Harry you silly boy, haven't you realized that attraction isn't a symmetric relation?"
"I hadn't even considered that," Harry admitted. "My plan is ruined."
"Not so fast. If we instead consider the Hogwarts population as a directed graph, we can partition based on strongly connected components."
"Brilliant! Per strongly connected componentem Hogwarts dividite," Harry cried out.
It was soon discovered that the entirety of Hogwarts formed a single strongly connected component, except for Snape, who was immediately ejected, but little else changed.