Imagine buying an entire gallon of bright pink paint, only to have it spill on the register as you're paying for it. This person doesn't have to imagine, because they not only did just that, but they also angered the manager of the store. I wonder if they had to pay for the paint, because they did technically use it, if only to give the self-checkout a makeover. That person shared the most annoying moment of their day to r/mildlyinfuriating, home of many, many, tiny irritations. One person igni…