<human>: Give me a shortened version of the text

Story:

I am a college student in the middle of exams; currently my head is in another world.  I placed my three dollar bills right behind the three boxes of kraft dinner I was purchasing.  I have placed money on the belt before, and I am not quite sure why I chose to do so now.  A man in his early thirties behind me started saying something, with a smile on his face.  I could not hear him, so I just politely nodded and said "yes" in agreement.  He looked slightly confused at my reaction, and as I was walking away he proclaimed loudly: "She's a person, you can at least hand her the money".  As I turned around, it hit me that the cashier was a Latina and the man scolding me was an African American.

So, if you would, tell me some of your stories of a similar vein and hopefully they'll make me feel better.  Or if you don't have a story, but have a faux pas you feel everyone should know, be my guest!
<bot>: I was just made to feel like a racist asshole, and I want you to make me feel better about myself, reddit.