> When someone in front of you walks in the same direction, you follow them. I had the exact same thought. It's logical. If you're moving across a crowded plac

> When someone in front of you walks in the same direction, you follow them. I had the exact same thought. It's logical. If you're moving across a crowded place and the person(s) in front of you are acting as "ice breakers", you naturally follow them in that direction as it is the easiest choice. If you're moving on your own (you're the ice breaker), you will tend to avoid other people according to normal "traffic rules", and assuming everybody else also does that you effectively have lines going each direction. Also unsurprisingly, if you ask people to "evade" to the opposite side this messes up the system.