Humans love to hate other humans that they feel (erroneously or not) deserve to be attacked in some way. It's been like this since homo sapiens first learned how to use a stick to beat someone else.

I man threatened me with a knife, one day, in an attempt at robbing me. I reached into my left pocket to retrieve my money for him and, instead, showed him my own weapon. It wasn't a knife.

Just because I'm paranoid, doesn't mean that they aren't out to get me.