The $customer gets a device from us, with th wifi connected as specified in the order. $customer connects it to the mains and monitor, puts in the dongle and the connection is established.
Fast forward 3 weeks, now everything went south. The device does not connect to the network, the service is offline. Our first question: "Has someone modified the WiFi name or password?"
$customer: "No, there were no changes in the WiFi"

So the full arsenal of debugging the connection over LAN starts, interrupted by $customer unplugging the device "because he needs LAN now"

After sometime, we figured out, everything is fine with the device, and ask $customer once again, if the config $ssid and $password is correct.

$customer: "Oh, we changed the name to $ssid2 because it looks nicer, is that a problem?"

Internal: "Are you f*kin kidding me? I asked you exactly that"
Me: "Alright, that explains the issues. Please tell us in advance if you want to change something with the WiFi."