My mom gets the same "Did you play basketball?" question. She's 6' and when she was in school, the coach did want her to play, but she's non-athletic.
Right after I graduated college, I started substituting to get some moving money. I had gotten a short-term stint at the junior high school. One day, I was walking down the hall on my break and got detention because I wasn't in class. The teacher thought I was a student. I was a bit offended as the students in the building were 12-15 and I was 22 at the time. But now I guess it's a compliment that I look so young.
Another thing that always happens is that my step-daughter and I get referred to as sisters when we go anywhere. And I love the look on their faces when I correct them since we're only 12 years apart.
JJ: Before I lost my 20+ lbs someone asked me how far along I was. That is what caused me to realize I need to lose weight.
I'm think of some of the worst things that could be mistakenly asked and I think "How much?" would be horrific.