The woman walking past me was having an animated conversation with no one. It wasn't her voice that caught my eye - it was her bright yellow shirt. I thought nothing of it, until we interesected again and I realized that she wasn't on a cell phone. Ten years ago my instinctive reaction to a fellow pedestrian talking loudly to someone I couldn't see would have been to cross the street. It struck me that now I assume s/he is on a cell phone, and hardly count the behavior as odd at all.