Trainee

His first day on the job, the trainee dialled the canteen and shouted into the phone: "Get me a F****** cup of coffee, quickly!"
The voice from the other side responded: "You fool; you've dialed the wrong extension! Do you know who you're talking to?"
"No," replied the trainee.
"It's the Managing Director of the company, idiot!"
The trainee shouted back: "And do you know who YOU are F****** talking to, you F****** idiot?"
"No!" replied the Managing Director indignantly
"Oh thank God for that!" replied the trainee and slammed the phone down.