Here's one you can all try!
I put the headsets (already plugged in) on the back seat while strapping in and then by mistake picked up the passenger's one and put it on. Air Traffic said they could only hear the carrier signal on transmit, and then me "very faintly" when I shouted!
One's first thought is that the radio is on the blink, then that the jack plugs are not fully home, and then finally that - erm - oh dear! A smug response from Air Traffic: "We thought that might be it!"
But surely I cannot be the first?