I was once people watching with a friend, and he pointed to a slightly older woman and said would you? So I said yeah, sure shes pretty hot in that tight outfit.
Now normally thats not something bad to say, or at least if yu do, its not exactly unusally and never really serious. However, a mother overheard me, and her daughter (she was like... maybe 12) had the same kinda outift on as the woman (same shirt and pants, so I tihnk the woman we were originally talking about just shops in the teens section), and thought i was talking abotu her daughter.
That was a rather awkward conversation when the mother decided to march over to me and tell me about how sick I was becuase GOD FORBID her assumptions of the situation which she had just ease dropped on be wrong.