The following story provides an amusing, though costly example of the real-world importance of JNDs, in this case, for weight. During an extended stay in Italy, a man we know went to the grocery store, taking with him the shopping trolley (an opaque bag on wheels) provided in his rental apartment. Returning from the store, he thought he had taken all his purchases from the bag, but a small bottle of laundry detergent was still inside. The bottle was light enough that the man did not notice that the bag weighed a little more now than when it was empty, and it still “felt” empty when he wheeled it back to the store a few days later. On the second visit, he again used the trolley as a shopping cart, putting new items into it. So imagine his surprise and frustration when he put all those items on the checkout counter and discovered that they included the detergent he had purchased previously. There was no way that, with his minimal Italian language skills, he was going to be able to provide a description of Weber’s law to convince the store clerk that he had already paid for that item, so he ended up buying it twice.