Some years ago while an F/O on F28s at PX we were operating on a QF flight number ex CNS for POM. Our Fokker was 'parked in' so we needed a push back and this caused a short delay.
After departure call to QF CNS went something like this;
Me " Qantas Cairns QF 123"
QF CNS " QF 123 go ahead"
Me " Cairns QF 123 off blocks xyz, 5 minutes late due Captain requiring a tug before taxi!"
Captain looks dumbfounded as QF Cairns tries to keep a straight 'voice'...unsuccessfully!
Chuck.