Could you stop complaining so I can take you order?

[Food Lady]

In cafe today and as usual, I walk into not enough food for afternoon snack rush, so I'm hurrying to stock when my first customer comes up. She orders one item when she gets distracted by some other customer in the background several yards behind her. I guess she doesn't like what the other person is doint because she says in a critical tone, "Oh, that's nice..." and I have no idea what she's referring to because I didn't see anything, since I'm paying attention to the person in front of me, you know? I ask if there will be anything else and she's snapped back to ordering. She finishes and then begins to complain about the people shopping with her, or something. idk. I don't answer when she asks for my agreement, since I don't even know who/what she's talking about. I just need you to order because I have things to do!