A video of you looking stressed or face-palming, then transitioning to a "glow up" or a cool photo.
The humor comes from the contrast between a strict grandmother and your unbothered attitude. Leaning into that "awkward" energy usually gets the most engagement.
Before any explanation could be offered (not that there is a good one), her leathery hand was already windmilling. Slap! Sandal thrown? Most likely. The classic sendal Jepit flying like a boomerang of shame.