They know exactly who we are. They know who strangers are. They are often very, very happy. Occasionally they get frightened by things that are strange or they aren’t sure what’s going on. The only thing they cannot do is speak to us in full sentences, but they communicate all the time.
I believe that not only dogs, but all animals can sense danger. I think it's just a survival mechanism and it allows them to survive in this harsh world we humans have created. A more simple explanation might be that animals aren't busy interacting with each other or using electronic devices, so they are more aware of their surroundings and can sense danger.
Dogs are more capable of feeling danger than humans think. These are remarkable creatures, and are trained for many things, including bomb sniffing and helping blind people. These skills require a sense of danger to keep themselves and humans safe. For instance, a seeing eye dog will not put his master into traffic.
Yes, dogs are able to sense danger better than we think. Their sense of smell and hearing can warn them of dangerous things approaching, and their pack instincts keep them more alert for things that can hurt their pack mates. These things combine to give them better danger senses than most people think.