1. Whenever ANYTHING happens in your life, they are the first person you text no matter what.
Whether you got a free upgrade at Starbucks, scored your dream lipstick on sale, or got a job promotion, you've just got to let them know.
2. Which means your phone is constantly going off with notifications from them.
You dread to think how many messages you send each other a day, but it's A LOT.
3. You love each other more than you could even comprehend loving a significant other.
You can't think what would happen if one of you started to love someone else this much.
4. You would 100% rather have a night in with your BFF watching chick flicks and snacking than going on a Tinder date.
Actually, you're starting to think dates are potentially worse than most other things you could do with your evening.
5. When you go on a girl's night, you end up having a better time when you're not out to look for guys.
Dancing by ourselves—that's where the true fun is at!
6. Your most used emojis are the two dancing girls, the sassy lady emoji and the flamenco dancer.
7. You get friend jealousy on a ridiculous level.
Even if you're not a jealous person and never find yourself jealous about significant others, it's a WHOLE different story with BFF envy.
8. Oh, but you also get on really well with all their friends and treat them like your own, too.
We all make friends at different stages of life, but your BFF's mates instantly become yours, too.
9. You've told them stories about yourself that you still find so incomprehensibly embarrassing you can't even bear to think about them.
But yup, your BFF knows about them.
10. You wake up spooning and cuddling like it's second nature.
What do you mean some people don't even share a bed with their best friends?
11. Obviously, your best/hilarious/most ridiculous memories happened with them and if you did get married, the wedding speech would be BEYOND juicy.
12. You're in with their families, too and treat them like your own—which sometimes means eating the last of their cereal without asking.
13. You spend most of your time full on insulting each other within an inch of your friendship or crying about how much you love each other.
That's true friendship, right?
14. You know what each other is thinking with a single glance no matter what the situation or what you're thinking, they just know.
15. You've stopped feeling embarrassed around them and can be totally yourself, which usually means forgetting all your manners and slobbing around in pambahay.
16. You've been on dates and thought something along the lines of "they won't ever know as much about me as my BFF" and sacked it off.
'Cos friends > boys, essentially.
17. When you're sad, they're the first person you turn to.
Forget boyfriends—it's this one particular BFF who always has your back. Enough said.
18. You essentially just love your best friend and don't really like the idea of you both actually getting married to other people and WHAT so for now you're happy in ignorance.
This article originally appeared on Cosmopolitan.co.uk. Minor edits have been made by the Cosmo.ph editors.