I get the "doesn't he get hot" question when Odie has a fly sheet on.
I've had the usual comment about braiding/banding on a boy horse and how they must hate it since it's for girls (I doen't even bother explaining stud vs. gelding).
Why do I feed horses hay & grain, it looks disgusting.
Do horses get baths?
What happens when you go on vacation, do you take them to a kennel?
I'm sure I'll think of more:)