What's something you can't believe you had to explain to another adult?

There was a bit of a language barrier when I served this lady, and at first I thought she was looking for assistance with a computer keyboard rather than a music keyboard. It turned out that she had damaged her power cable and wanted to seek a repair. I said that we could put her in touch with a manufacturer to see what service they offered but she was unwilling to pay an extra charge. My next effort was to sell her a multi-volt adapter, but she was scared that the same situation would repeat itself; and that she wouldn’t know what setting to use. I then wondered if it would work on batteries. She did think it would run on batteries, but she was unsure of the model number or which batteries to use or where they should go. I ended up bringing one out of the storeroom and demonstrating how they should fit; and she bought the batteries regardless without us knowing if they were the correct size. She hasn’t been back (at least while I’ve been in store) so hopefully all is well…