People watching or crowd watching is the act of observing people and their interactions, usually without their knowledge. It involves picking up on idiosyncrasies to try to guess at another person's story. For some people it is considered a hobby, but for many others it is a subconscious activity they partake in without even realizing. We decide whether those sharing our space—even temporarily—are smart or dumb, interesting or dull, and happy or anxious. Knowing nothing about them other than their facial expressions, what they’re doing, and the way they walk or sit.