My school had us enter our IDs into a keypad to buy lunch, so I did this everyday. Then, I had to enter it in a computer and got annoyed as the system wouldn't take it. Turns out the differences was that the lunch keypad was set up like a phone with 1 on the top while computers were set up like calculators with 1 on the bottom. It had become muscle memory and I was swapping two digits because of the change in entry device. Ever since then I've thought the incompatibility baffling, as well as surprising that it doesn't cause more problems. I hadn't noticed it at all until then.