1. You have countless memories together that you bring up constantly.

"Remember that time mom abandoned us at the family reunion?"

2. You probably have a group chat with them (and use it constantly).

And it probs has a weird name/inside joke.

3. You will make fun of them at the drop of a pin.

You're just constantly teaming up on each other.

4. You're so used to exchanging insults that when other people insult you, you barely register that.

You're first thought is probably something along the lines of: "That wasn't even a good insult."

5. But if anyone else tries to insult them you will shut that down in a second.

Only you can pick on them.

6. They're friends with your friends and vice versa.

And you sometimes need to clarify that it's your best friend coming over.

7. Other people don't understand why you like spending time with your siblings.

Your high school friends tend to get it, but your college friends are confused.

8. You can throw out obscure/weird movie quotes to each other and they'll always get it.

Bonus points if you can use a quote as an insult.

9. You're arguably too blunt with each other/ fight too aggressively.

It's fine, you know you're legally obligated to love each other.

10. But once the fight is over, it's pretty much forgotten.

11. Your friends always point out how similar you act and talk.

12. You get super competitive.

Board games can get slightly dangerous.

13. You can talk to each other about anything.

14. You argue about whose kids will be cooler.

15. You're always super proud of their accomplishments.