What Do Blank Stares Show?

Blank stares are usually given when you're in deep thought, right? But what does it show toward others around you? Anger.Sadness.Pain. These are answers that people usually see when the blank stare is given. Even though the deep thoughts could be about happiness or the bright future, people will always think blank stares show a visage of anger, sadness, or pain. Why? What if I just have nothing to say but to just want to be in deep thought for some random reason. Do emotions show in blank stares? These countless questions could be endless so I'll just end it here.