That's okay. I'm talking about purchasing things in a store setting. Not all things. If we pay attention it will be better all the way around.
However, there is no excuse for the behavior of the store owner. That response belongs to her and her alone. She is not a nice person. Even if the customer is rude, she should step above that as a professional and handle it respectfully. In this case it is a very nice person so she can't even use the excuse that she was defending herself from a very rude and nasty person.
I deal with parents on a professional level and they can get upset when it comes to their kids. I have been yelled at and sworn at twice in 16 years but I did not do it back. I kept my patience and was respectful. And believe me with someone in your face it is hard. It is easier to fix something that is broken than to try to fix something that is destroyed. When you take respect and kindness out of a business relationship you usually lose that persons business and many more. It's hard not to like someone who is kind and respectful. Just look at the success of conartist. lol They are usually referred to as kind and respectful.