1. We didn't choose each other, but we're stuck with each other.
2. We see each other at our worst, at our best, and everywhere in between.
3. We go through really extraordinary circumstances together, and no one else can really "know" what we've gone through. We just look at each other and get it. We get each other's jokes in the same way. Just a few key words are all you need, and it's instant mutual understanding.
4. No matter how much we annoy, dislike, or resent each other in normal circumstances, when something bad happens we are instantly there for each other.
5. We know each other really well. We know when someone is in a good mood or a bad one. We know what type of patient or situation we're good at or prefer. We know how to pick on one another or push each other's buttons, but we also know each other's strengths and draw from them.
Yeah, we're a family. Not all friends, not all buddies, but a family.