If they ask, I tell people that I am crazy. Then I saw something to the affect of, "when I find a big kettle of crazy, I find it's best not to stir it". It was on Dilbert or something.
For the most part they just accept that I'm outside of social norms and leave it be.
One lady told me I was going to die the other day. I said that at least I'd have a smile on my face.