Why do Wordsworth booksellers make their customers uncomfortable?

Last week I was in Wordsworth in Somerset Mall. Firstly, the booksellers were quite unfriendly and I just assumed they're having a bad day. Ah it happens. However as my husband and I were browsing, the female bookseller started walking up and down, so obviously watching us. We have an array of interests and we were looking through different categories. When a white woman came in, the same girl beamed and asked "how may I help you?". Now, I try not to bring it all down to ****** but she carried on eyeing us as I was looking through books and politely spoke to a few more white people that entered. Why were we not given the same treatment? I smiled at them as they came in and they looked at me as if I was mad. Weird. I actually came there to find a low carb book, and I would have bought a few had she not made me so uncomfortable. I wanted to ask her what her problem was but my husband held me back. I'm not even scruffy looking. I'm just BROWN. My goodness, have they never seen brown people interested in books before? I will never again set foot in Wordsworth Somerset Mall again. I got what I wanted from Exclusive Books & the booksellers were helpful and friendly. I didn't get their names. The girl and guy were both young, early twenties. She had long brunette hair. This happened around 4pm.