Because it's your team! Your country! Your boys!

Imagine your kid, or best friend, or parent doing something amazing. Would you celebrate? Of course!

Some people can muster something akin to those feelings for strangers, because it feels like they're part of that group. And add millions of others who feel the same way and that feeling gets amplified.

Heck, you don't even have to be a part of the group, you can just be rooting for a team for some random reason like them being the underdog or liking the country because you went there once.