some other good ones from our training:
during emergency training: one acft cruising at FL330, crossing traffic at FL310, and (murphy :-) the upper one had a engine failure. so the pilot reported "DLH123, engine failure, leaving FL330 for 220", then the atco-trainee screamed "negative!!! maintain FL330!!!"
or another one , a B747, wanting to climb to FL350 from FL310. trainee asked "SIN123, ready for higher?" "SIN123 affirm", atco: "roger, then..." then he realised he had opposite traffic at FL330 "maintain FL310!" must have been a bloody disappointment for the 747! but the funniest thing was then the reaction of the coach (can't be translated..."sowas nennt man pilotenverarschung!!!!!")
was the best time of my life the training in ATC.
cheers,