My favorite "heard on the radio" story involved an anonymous character.

It was the wee hours of the morning, not a lot of air traffic, but some. After a long period of silence on ATC frequency a radio breaks squelch, and a voice is heard:

ANONYMOUS: "SIGH. I'm fuckin' bored."

ATC CONTROLLER: "Caller transmitting on 123.4, this frequency is reserved for air traffic control. Identify yourself immediately!"

After a brief silence, with everyone on the frequency waiting to see what would happen, the same voice:

ANONYMOUS: "I said I was fuckin' bored, not fuckin' stupid."