Order a milkshake, go in the bathroom and take a shit in a milkshake, go back to the counter and say, "Try this milkshake, it tastes like shit!!!"
And if they do try it.....
:carling:
The following 7 users say thank you to Done #3 for this useful post:
go to the counter, ask the person to read out something on there, and when they turn around to read it, walk out and they'll be stood there talking to themselves
Order a double cheeseburger, eat half of it, tell them you didn't want tomato sauce on it, ask for a refund or a new one without tomato sauce, get your new double cheeseburger, eat it and tell them thanks for a free double cheese burger, and run