People watching has always been a favorite pastime of mine. People are never boring. They’ll always surprise you.

I often feel a little shame when I do it, though. Sitting at the coffee shop window watching passersby, one feels like bit of a voyeur.

Of course, there is a line that separates human curiosity from voyeurism. (Unlike Jimmy Stewart, I don’t use a telescope.)

Anyway, it was inspiring to read a post on Marketing Profs by Lewis Green about watching people in order to become a more effective marketer and salesperson. Lewis wrote about his experience observing people at the airport. (Perhaps the best people-watching venues in the world are airports.)

It bears repeating that the best salespeople are keen observers of human behavior. They’re aware. They pick up physical cues. They look for clues in a person’s posture, dress, and tone. They know when a smile is real or fake. They know when their pitch is working and when it’s not.

Less effective salespeople are more detached. Less interested in others, they’re more concerned about themselves and closing the sale. They have a spiel and façade that don’t change. That spiel may be compelling and the façade impressive, but they’re static. Less effective salespeople don’t read each situation and adjust accordingly. A lot of the time this approach works. Except when it crashes and burns.

The point is that the world—the airport, the grocery store line, the coffee shop—is the saleperson and marketer’s laboratory. If you’re not observing, you’re not improving.