When my grandmother would take me shopping (I was around 5 I think) I would wait until she was busy looking at something and sneak off to the customer service desk and have her paged over the loud speaker because it was amusing to see her embarassed. The first time it happened was an accident, but then it soon became a game to me. I didn't realize until I was older she was playing along too lol. She had some experience with enxp's.
At around 4 my grandmother was having her house renovated, I painted the back of her house as high as I could reach with some left over paint left in the backyard. And then I painted her ceiling when someone left out a ladder and paint when they were doing renovations. I also stepped in a spackle bucket and then ran around on new carpeting. Poor grandma.