I don’t know if it’s just me, but it really bothers me when I’m soloing drive-thru and I greet the person at the box and politely tell them to wait. This is because I need to help the other customer at the window and the person at the box sighs or mutters something, which I find rude. Then a minute or so later, when I take their order, they don’t even know what they want! They were so upset about having to wait and didn’t even bother to think about their order.
Also, it really bothers me when a customer tries to add several food or drink items at the window! It’s like, dude, I have your order complete and ready to hand off and the orders for the next two cars and now you’re going to slow down our time.