People just don't get it and how could they if they don't experience it. Yes I agree people are scared. They think we're going to flip out at any moment. Again, part of not understanding. I have a friend who just wasn't getting it and I had a real hard time trying to explain it so I sent her onto the web to research it. She did and came back with a better understanding.
As for new people in my life, I don't say anything. When I'm symptomatic, I just stay away or explain it away somehow.

I've lost many friends, one being a friend for 34 years because of this illness. The real friends will stick around no matter what.