Customer Service

I work at a local grocery store. The store has great deals on food, household items and clothes. And because we have these good deals, people flock to our store. Sometimes I think to myself, it's like 50 thousand people wake up and have one thing on their mind......lets go to(my store name). So there are customers from all walks of life coming there. But the ones who really get under my skin is the mean ones. There was this lady that just looked mean so I kind of prepared myself for whatever she was about to bring. I start to ring her out and she wanted to take an item off the order. I said to her that I don't have the authority to take that off. She said to me in the meanest way possible" I didn't ask of you had the authority to take it off". I tried to explain to her once more the situation and she got even more irritated with me so I completely ignored her and directed everything to her mother. I am very good at acting like someone does not exists. I did that so that I would not sin in the eyes of God. The day before yesterday a customer came in and said something that caught my attention. She said people are so caught up in employees to give good customer service, well people should be good customers!!!