Dealing with rude people/customer service

I have worked in customer service for most of my life, although I’m introverted I do enjoy my job and for the most part the regulars that come into my store (retail), lately I have noticed a few people who come into my store that act as if they are entitled to everything/ know everything about our store policy and customer service. There is an older women who has told me that I should “smile more” despite me always minding my business while I am working. I’m pretty good at ignoring that type of childish behavior but otherwise feel pretty targeted by her. She has also told me that in every situation “ the customer is always right” to which I responded with “ not me, welcome to the real world”, she made a big deal about this and even told my store manager to which she laughed at. A few days later she came back into my store and approached me with the saddest most fakest face and said “ I would very much like it if you answered me with a smile and treated me with a lot more respect, I am older than you.” This completely blew my fucking mind and I actually laughed at her. I am 25 years old, I was raised to respect people but this idea of “ because I am older than you” is fucking hilarious to me. While I was working she made it a point to step in front of me on purpose and told me to “ pay attention to my surroundings and the people who shop in the store.” And “ Without a smile I am scaring away customers. I simply walked away from her and her response was to make a scene by saying “ You’re an awful person to be working in customer service. I can’t believe you would treat a person like this!”

Edit/ Ongoing

I brought this customer up to my general manager and her response is that “ Kill them with kindness. I promise you that that persons shopping experience here is your paycheck. If she is asking you nicely to smile at her then do so without a smart ass remark and without any attitude.” I argued my point and told her “ Every time this woman comes in here she goes out of her way to disturb me working on the floor. The only thing she ever asks me is if I can go lower on an item, open the bathroom for her or complain about my face and ‘lack of customer service/helping her with an item.” To which my general manager responded with Welcome to customer service. Smile more.”