Not so long ago, I tried to use the payment terminal of a Ukrainian bank.
Only 5 innocuous clicks on the touch screen opened for me access to the Windows Explorer of this terminal.

Three large buttons were available on the terminal's main screen: “Banking Services”, “Payment for Services” and “Restore Receipts”.
Advertising of bank products and, roughly speaking, mobile replenishment / payment for the Internet is not interesting for me.
')

But how the function “Restore receipt” is arranged - I was interested (for example, in the bank where I work, there is no such function in the terminals yet).
I press the above button. A screen opens where you need to fill in two fields: “Requisite” and “Date”.

I do not specify data in the first field, in the second the date is preset automatically, so I just click "Print".
Waiting for an error message. The error message I get is not quite correct (“Enter the identifier”, despite the fact that the field is called “Requisite”), but oh well.

I press the only available on the “OK” screen and press “Exit” - I did not see anything interesting.
But here for a split second flashes open conductor.

It seemed? I try again: Receipts, Printing, OK, Exit - no, it did not seem.
For this split second, I try to click on the folder tree on the left, and it succeeds - the computer goes to the folder and displays its contents.
I mentally tell myself that after the terminal has gone to standby mode, something will surely get lost, I try again - however, the same folder remains open.
For the next split second, I was able to see which programs are installed in this terminal.

Then he was able to open the Network Neighborhood and be surprised that there are so many devices here (especially amused the names. And what? Bank staff are people too!)

In general, since the terminal is inside the bank, I did not want to look at it for a long time, so I left.
I called in support, they said that the error message needs to be written to e-mail. I sent a message to e-mail with a picture, but this did not speed up the process - I was contacted only after a week and a half. Solved the problem somewhere else in a week.
Total? Such situations occur to me constantly, despite the fact that everything has long been studied and described. The notorious human factor still gives work to testers.