What makes people compatible?
That is one of the biggest questions I have. But I have worked out somewhat of an answer recently.
People aren't compatible because of common interests or common backgrounds. These are simply things that strengthen two relationships by eliminating some potential for disagreement.
But ultimately, what it comes down to is talking. When you are with someone you are compatible with and talking to them, there is never a dull moment, you aren't trying to impress, you are laughing, you are smiling, and you aren't holding back. A person you are compatible with is someone you can talk to all day and all night without thinking twice about what you are saying. The are someone you can tell anything and everything to. And they are someone you miss so desperately your heart aches without them.
This is what I have come up with. But who knows, maybe I am wrong.