If you made a mistake in an order, would you still present it to the customer with an explanation or would you dispose of it?
Your response to this line of questioning should give a snapshot of the type of barista you would be and how adaptable you are when presented with some hypothetical challenge or situation. Telling stories makes for a more memorable interview, and you can use storytelling to show how you handled a similar situation and what the outcome was. It's often a good idea to end on the question with a response that will help to turn the interview into more of a conversation. Ask if you answered their question adequately or if they'd like to hear more information.