A long time ago I was flying a beater Islander delivering newspapers in the very early morning. The frequency was as actually pretty busy as the terminal controller was working several sectors., when terminal asks me for my indicated speed. One thirty I replied with a mental addendum "Like always, wadda yah thinking ?"
.
Nothing back for quite awhile as he talks to other airplanes on other frequencies and then another call again asking for my airspeed, I am about to say one thirty again.... and then just for the hell of it, elect to reply "Mach.15"
A pause and then I hear after a bit of a chuckle "check you are indicated One Three Zero"