People watching arises from boredom. It is a way to amuse oneself. A lot can be learned about someone with just one look.

When someone is people watching, the first thing they notice is the clothes the person is wearing. A way a person dresses is essentially the image they wish to convey to others. Those who dress in designer clothing are presenting that they are affluent and fashionable. Those who wear tattoos are displaying something permanent that represents what they value.

The way someone walks can determine their self-esteem. Those with a confident stride and good posture are displaying their security and happiness with their well being. On the other hand, those who shuffle their feet and slouch when they walk, are displaying a sense of insecurity and self-doubt.

Observing anxiety is common when people watching. These people constantly look around and are particularly fidgety when it comes to posture. Many times these people will hold their belongs close to their bodies as a sense of protection. Similarly, those with stress will perform these acts as well. Like anxiety, those with stress have something on their minds. With stress, however, people watchers can see the burden that is carried around. People with stress also tend to be preoccupied with their phones.

There are various other traits observed in citizens through people watching, including, but not limited to niceness, and extroversion. While people watching is a great way to pass the time, people watchers make very biased observations. People watching is by no means a definitive answer to who someone is. Even though body expressions and appearance tell a good deal about the person, the observations made by people watchers are just that, observations. Conclusions can not be accurately drawn based on observations alone.

https://www.psychologytoday.com/blog/fulfillment-any-age/201504/the-experts-guide-people-watching