Even though we subconciously know that supermarkets don't clean their shopping carts, we've convinced ourselves otherwise because the truth is disgusting. The best cleaning that most carts ever get is when they're left out in the rain, and that doesn't do much to clean away the germy mess.
Shopping carts are coated in a disgusting mix of bacteria, raw food, and even fecal matter! In fact, a study proved that 50% of carts are infected with the dangerous E. coli virus. From now on, make sure to give your cart a good once-over with disinfectant wipes before using it.