Histrionic knee-jerks reactions are a common response to fear. Numerous people here are simultaneously announcing that they are protective of their personal space, and lashing out at the article -- one person even admitted that it triggered his &quot;flight or fight&quot; response. All of this is anecdotal proof of the thesis.<p>(Just as an additional anecdote of the flip side of this, I have no personal space issues -- I like crowds and subways -- and have somewhat reckless tendencies)