In a story I recently read, Pandora's Star, the human race becomes concerned about a shield -- an apparent force field -- that envelopes another solar system. Why would anyone need to be shielded unless they were a threat? If the shield is a defense, then -- so the reasoning goes -- they're likely to go on the offense.
Although it's only a story, this sort of reasoning is applied to people like me on a fairly regular basis. I've tried to understand it over the years. If I spend too much time alone, or if I don't spill my guts to everyone who wants them spilt, it tends to make people uncomfortable. Liking my privacy has never been an acceptable answer. I think the reasoning goes like this:
I can be private as long as I'm not noticed. If I choose to be in the company of others, or to make myself noticed, then I'm asking to be questioned. If I choose to remain quiet in company, or to remain apart, shielding myself from others, so to speak, then I must be hiding something. And if I'm hiding something, then there must be something troubling me; anything troubling me is likely to become dangerous for others later on.
Or, at least, that's how I imagine the onset of fear progresses.
Not everyone minds having a quiet person around. But it's a rare find. It's a kind and accepting nature that allow others to just be -- to join when we want, to talk when we have something to say, to stick around even when we're not entirely involved.
A shield isn't necessarily a danger. Sometimes it's just a way of life.