I really hate myself for it

While it hasnt made me racist in the least i still understand what youre saying. Ive worked retail for 6+ years.

My moms a ER nurse and she has said the same thing.

Working in police records.

Growing up with a father and uncles that like to dress up like cone head ghost made me racist

Running 5k made me racist

When I worked in retail, I loved the elderly if they were really sweet and patient with me. When I was a cashier, some of them would try to tip me but I had to deny because it was against company policy.
But then there was the old hags that expected you to know everything and would try to cheat out of higher prices and fight with the manager about it.

It did the complete opposite for me... I just realized there's people in every race/age group/gender that are assholes

All working in retail did for me is wish a fiery end for most of humanity.

Working as a nursing student in hospitals, geriatric (elderly) patients were by far the most difficult.

The only time anyone's not racist is in front of other people. Everyone's slightly racist.

Retail does make you anticipate what you are going to be dealing with.. However, you are only racist / bad at your job if you are not opening to being wrong about your initial assessment. As a manager I prejudge people, but then I offer assistance and listen to what they tell me, rather than just assuming.