When I see armed people, my first thought is often: Now we are all a little safer. I personally think both that "shall not be infringed" means what it says and that it's a good thing when people exercise that God-given RKBA (and "bear arms" means we can carry them in public). It will be nice to see the change in attitudes as more people adjust to "scary" guns in the hands of good people and not just criminals.
Unless they are police officers, then I first look to see if there are any dogs around. If not, I breathe a little easier.