I'm with Fragola on this one.
I've worked in retail most of my life. I know that every customer is a potential sale, but it gets fairly easy to distiguish the 'real' customers from those who are inspecting, or comparing product to something they already own/make/sell - they ask more questions; which at times can be quite confrontational, and they are quick to point out the faults in a product.
I'm not saying that you were confrontational, or picking holes Newbie, but perhaps she misread it to be that way.
I did it in LUSH the other day, I inspected everything and was grossed out by there unpackaged soap that was covered in hair and dust and when I was acknowledged by a sales person I was acutally really short with them - I walked out and couldnt believe how I had acted. :shock:
My guess would also be, that if she is selling well she must have some regulars, which means her product cant be all bad.