I don't know how to put it well, but in certain settings alarm bells go off in my head as to the imminence of danger. I don't think it's prejudice; it's some atavistic instinct that something is just not right, that I ought to be on guard. I can't link it to specific, repeatable themes, but it just occurs.
Naturally, feeling that something might be amiss and taking precautions is better than to ignore those senses. The cost of taking steps to avoid the situation is less if I'm wrong than failing to take sense and being right.
I grew up in the suburbs of Nashville. Some, nontouristy parts of Nashville are less desirable, I must say. But the place that makes me real uncomfortable is Cocke County, TN and some places on the Cumberland Plateau.
Memphis, Atlanta, and Birmingham are statistically dangerous, and I am very careful of where I go after dark.
The reason why I'm nattering on about this is that I might move to Seattle. There are some parts of that area that I'm not sure about, like Pioneer Square or Belltown. Anyway, I have to balance safety and affordability. I would like to live on one of those islands across Elliott Bay, but doing that takes $$$.