Back in the days where the "All Stations" ATC call used to be "Combine", I was taxying out at Swinderby in my Chipmunk, trip 3 I think it was. Beautiful summer's day and there we were trundling over freshly mown grass.
"Swinderby combine, Swinderby combine. New QFE...(blah, blah)."
Smack on back of scooter helmet by understanding ex WW2 instructor. "Why didn't acknowledge the new QFE?"
"Sorry Sir. I thought they were talking to the grass cutter."