What can customers do to make your life at work easier?

As someone who has a customer service job i try to be helpful and easy to deal with when im somewhere where im the customer but sometimes i feel like i dont know the right way to do that. For example when i go out to a restaurant i stack the plates and put all the napkins and straw wrappers and random garbage on top of the stack and kinda have the silver ware in a bunch off to the side or on the stack but not mixed into the garbage. ANYWAY i was just wondering if some of you could share ways that a customer could make your job easier or something that customers do that they think are helpful and actually make it harder on you?