Drive thru weird experience

At approximately midday today I went to the kfc drive thru, observatory cape town. I got to the window to fetch my food, a lady then told me that the food isn't ready so I should reverse a bit so that I cant see inside???? Honestly this was incredibly weird, why would she make me reverse? I then had all the cars behind me hooting. I would really like an explanation to this. I'm sure you can also view it on your camera system.