It was my second year of college and I was walking back to my dorm one night (I attend UC Berkeley and it's fairly open to the rest of the town, Berkeley, itself) and I wasn't with anyone and it was a more secluded, quieter, darker side of campus.
So, anyways, out of nowhere comes these 2 white kids (Just like me) with a knife, demanding I hand over my money. Just as I'm doing this (I'm 6'8" 240 but I'm not going against a knife) some black guy rounds the corner behind the white kids. He just goes "WHAT THE f***?" and pulls a gun out of his waistband. First thing I think is "Oh f*** we're all dead" but he just approaches the kids, tells em to put the wallet, cell phone and the knife they had on the ground. They do and then they ran. The guy just tucks the gun back in his waistband and smiles at me. I was kind of nervous but really f***ing thankful, so I offered him some cash for possibly saving my life. He said "No, I'm fine. I'll get my payment eventually. There's benefits to being a good guy, right?" I nod and laughed at him.
However, right before I left he asked if he could use my cellphone. I handed it over and he made a call. Turns out he was on his way to Christmas shop and had forgotten the list so he needed to call his uncle back and recheck it.
I have never met another human being like that again. He changed my perceptions of minorities forever.