Dear Prudence,
I work in retail. One day I came around a corner and saw a customer facing away from me. A co-worker was approaching him from the other side. Usually I would go up myself and see if I could be of assistance, instead I backed away quietly. Why? The customer had a swastika tattoo on the back of his shaved head. I could hear him speaking with my colleague, and she found him what he needed. (And I hope she turned and walked away from him and thus never saw the back of his head.) I judged him and I discriminated against him based on his appearance. Did I do something wrong?