People tend to gravitate toward friends and partners with whom they share common interests, backgrounds, sometimes even physical characteristics. We set up expectations for how this other person will interact and react with the world according to suppositions we make based upon our own self concept. We rationalize that the other person is so much like us, that with full authority we can set up expectations for their behavior. After all, if they are so much like us, and we know how we'd react, we can know how they'll react.
It's human nature to want to align with those in whom we see ourselves (including those wackos that get dogs that kind of look like them). Unfortunately, the only result we can count on from setting up expectations for another person based upon how much they are like ourselves is disappointment - and, hell, maybe even resentment(!).
So now what? You're pissed at your friend or partner because in the face of some adversity they didn't face it the way you would have. Or maybe you're frustrated over a difference in communication style or frequency and think that they should just *know* that that irritates you, because well, they are a mirror image of you, right?
When finding ourselves caught in this relationship trap, approaching from a new perspective that celebrates the differences we have with the other person can be hugely instrumental in lessening the burn. Acknowledge the novelty of the other person and get *actually* curious about what makes them tick. The reward that comes from investigating and cherishing the differences from ourselves in the people we hold close grants a new lease on an old relationship.