My stepsister didn’t have a job, and she kept using my expensive shampoo. When I told her to stop, my stepmom called me petty and selfish.

So I added a bit of blue food coloring to my shampoo. Not enough to damage hair—just enough to give a tint over time. Two days later, my stepsister freaked out over her “weird bluish tone,” blaming the water or the shower filter. My stepmom had no idea.