They associate with people who like a team. Then they begin to like it on their behalf.
A lot of people just choose the closest team to where they live. But I consider that boring and unoriginal. This is different if it’s your actual city though. Then it’s just city pride. You have to go with it.
As a New Yorker I chose the Miami Dolphins because it’s my dad’s team and I grew up around aqua and orange. Also most Buffalo people come off as obnoxious dicks that like to break tables like frat boys and I don’t want to be around them.
Other options could be as simple as I like their jerseys. They look cool. Because you will most likely wear the jersey eventually.
A fascinating discussion when you live in the arse end of Ireland and discover that most people are fans of this team or that team… all of which are English.
If it’s your city’s/country’s team, has historically been your family’s team, there’s a player you particularly like or there’s something special that makes the team stand out (eg I support Chivas/Guadalajara becuase they only hire Mexicans). It has little to do with sports, tbh. I know very few people who support a sports team on its sporting merits alone and they’re all insufferable.
