One of my favorite things to do in a mall is to bring a sketchpad and quickly pencil out the people I see in the food court. Typically, I only have a few brief moments. Some get self-conscious and discover what I'm doing (because I intermittently stare at them); some never notice. But it has to happen fast. It's a good exercise.
I'm an artist, so this is what I do.
You have talents... what do you do? Study their clothing? Their relationships? Their purchase decisions?
Malls are a wonderful study in human behavior. How do you make the most of the opportunity?