Consider this scenario: you’re meeting your friend’s new partner for the first time. Your friend hasn’t told you a lot about their partner, but you know things are getting pretty serious. The partner greets you with a genuine smile and solid handshake. So far so good. You get to chatting and discover that the partner grew up in the same suburb as you, and went to the same university … what are the odds?! Then you find out they also follow the same football team as you -- instant approval!
But … what if they had given you a limp handshake? Grew up on the "other side" of the river/city? Went to a uni that wasn’t as good as yours? Or don’t actually follow football (shock horror)!? How would you be feeling about them then? And does that really have anything to do with how good a fit they are as a partner for your friend?