I also like to observe. Watch how people interact with each other. Listen to the things they say (and more often, the things they don't). Analyze the possible motivations behind these actions, and then, in the best circumstances, actually get to talk to people about all of this. Talk about the how and why behind what they do (and what they would rather do). A good second place to actual conversation is an excellent book/play/movie/show that also documents such interactions.
It baffles me how some people are able to just do and not reflect or wonder or regret. I'm overstating things a bit; I do just hit snooze every morning without a second thought.
OkCupid should add transit preference to the "My Details" section. Especially in Philly, people seem to be quite partisan about their transit options. I'd say walking and biking tied (ETA: biking has taken the lead), then SEPTA. "We're getting there." is my favorite slogan ever. So great.