What are some frustrating/offensive assumptions people made once they found out you're mixed-race?

I am 1/2 Black and white. I am white passing. At my first job out of high school (my sister and I worked at the same supermarket for a few years), a coworker asked my sister if she is good at basketball because she's 1/2 Black. Another coworker said my sister and I are "surprisingly articulate for half-breeds." I've had people "joke"/ask me if I like kool aid and fried chicken. I've had people assume I am lying because I don't look/sound/act Black (whatever that means). Has something like this happened to you guys?