The look in a person’s eyes. Their tone of voice, small things about the way they dress or walk, or how they respond to certain stimuli. All of these small details will tell you a whole lot about someone, but most of us are so caught up in ourselves that we don’t even pay attention.
As adults we are all very good at hiding the things we don’t want anyone see, but everything leaks out in very small doses — which means you have to pay rapt attention to catch things that you’d otherwise miss.
Think of your pet dogs: They seem to know exactly what you’re thinking and how you’re feeling all the time. How? Because they pay complete attention and are completely tuned into you at all times. It should also be noted that dogs can’t talk and have small, less complex brains that humans — two huge reasons why they’re so good at paying attention to others. Consider that.