My grandma started walking five miles a day when she was 60.

This joke masterfully sets up an expectation of a heartwarming tale about the benefits of exercise in old age. We hear about a grandma who started walking five miles a day at 60, and our minds immediately jump to visions of vibrant longevity and robust health. The humor then pivots sharply with the reveal that at 97, her whereabouts are entirely unknown. This is classic misdirection (Review), taking a positive premise and twisting it into an absurd, darkly funny outcome.

The comedic genius here lies in the unexpected, almost accidental, consequence of her impressive dedication. Instead of celebrating her fitness, the punchline suggests her relentless routine has led to her simply walking off the map. It taps into a relatable, albeit exaggerated, anxiety about elderly relatives maintaining their independence, sometimes to a fault. The irony is delicious: her commitment to health became the very thing that made her disappear. It's a playful jab at the idea that sometimes, too much of a good thing can lead to hilariously unmanageable situations.