School
Explanation
This comic takes the classic kid question "Why do I have to go to school?" and turns it into a darkly honest answer about the realities of family life.
A child asks her mother why she has to go to school. The mother's answer is blunt: "Because when you're at school, that's when Mommy and Daddy screw." Rather than offering an inspirational reason about education or learning, she gives a purely practical, adult-world explanation -- school provides parents with the privacy they need for intimacy.
The child protests that she could just stay home, and the mother elaborates on what that would entail: covering her ears against "tannins" (tantrums of noise), moaning, and "rattling of chains" that would look like "the Jacob Marley scene from A Christmas Carol." The reference to Dickens' ghost, dragging heavy chains and moaning, is played for laughs as a description of the parents' bedroom activities.
The child then delivers the punchline observation: "You've simultaneously ruined home AND Christmas." The mother cheerfully agrees: "Which is why you should go to school." The joke works on multiple levels -- the child's innocence is shattered, two safe havens (home and the holiday) are destroyed in one conversation, and the mother's reasoning, while horrifying to the child, is perfectly logical from the parents' perspective.