Most people seem to be too apathetic to be dangerous. I also believe there is more good than bad, whatever you will define that as. Most dangers are accidental or natural.
I don't open up to strangers or pay them any interest (I don't even know my neighbors) but I wouldn't abandon them if they needed help. As far as being friendly to everyone, it's pretty easy. But legitimate care is in short supply and not everyone gets that treat. I don't expect it in return either.