Doing the machiawase (setting up a meeting place) is one of things that define Japanese relationships, especially relationships in Tokyo.
Elsewhere in the world, people can just drive to each other's houses and socialize there, but such a practice is uncommon in this city, where everyone lives at least an hour's train ride away from everyone else. Getting together entails selecting a meeting place, and the person's choice of venue is an indicator of his or her personality, and the degree of intimacy in the relationship.
If you're under 25 and on a first date with Shibuya as your destination, then 80 percent of the guys will suggest "Hachiko-mae (in front of Hachiko, the dog statue outside the station)," upon which the girls will ask "atama, soretomo shippo (the head or the tail)?" Hachiko is perhaps the best-known machiawase spot in Tokyo, and clusters of people gather around the tiny statue at any given time of day, scanning the crowds for their machibito (the person one is waiting for).