As bad: access card readers that beep once to tell you they've read your card successfully, and beep once to tell you that they've not read your card correctly, meaning that you look like an ass when the revolving door spits you back out again.

At least beep twice for a failure, you stupid device.

To be fair, this particular device does have red and green lights on it, but you can't see them once you're halfway into the revolving door and waving your card at the reader.