In my opener about Ulty I wrote that you end up with more styles than positions in playing ultimate. Each player needs a generic ability to play all positions. Flexibility.
This combined with the integrity that is required with Spirit of the Game generally means you meet some quality folks on the fields.
You can discover more about a person in an hour of play than in a year of conversation. -Plato
Generally the mentality required to be good at ultimate and to enjoy playing it brings a certain attitude. This attitude breeds a way of relating to people.
In the city moves & relocations we've gone thru I've always managed to find ultimate in the town & quickly makes friends through it. Teams form of like minded players and friendships are forged through practices and tournament. Even if it merely stays at the pickup level, you find yourself dwelling afterwards or stopping somewhere afterwards for a brew to salute the end of the day.
Even after a hat tournament (random teams of players) I find at the end of the day I've been playing all day with my friends, I just didn't know it at first.