The crappiest bug I had was at one store - instead of using the recommended kit they wanted a cheaper solution so opted for a different barcode scanner but stil

The crappiest bug I had was at one store - instead of using the recommended kit they wanted a cheaper solution so opted for a different barcode scanner but still reputable from a reputable supplier. Store started complaining about sometimes scanning muffins - this was where the price was embedded inside the barcode - the prices were ridiculous for muffins but the barcode has a luhn check digit. Must be our code management said - so we looked at our serial driver until we eventually found evidence through logging all serial I/O traffic that it was the barcode scanner that was sending back a corrupted barcode. I would more worried what you can't see - SSD controllers - yikes don't want to think about the bugs in those things.