Marriage agreements usually go something like, "to have and to hold, in sickness and in health, 'till death do us part," yeah, yeah, we get the picture. If you hypothetically swap your fiancée for your best friend, the same rules apply. Well, maybe it would be something a little more like "to have more than a few drinks with and to hold your hair when you've had too much, in sickness of all forms and in every time of the month that you want to binge on brownies and any carb you can get your hands on, and 'till something stupid we decided was a good idea gets us killed." Yep, that sounds about right. Whether you have that one person or a few of those people, you're best friends for life, and here are a few times you were either painfully or blissfully aware of that:

1. You have all but shared a blood seal (and if it weren't for your mutual fear of needles, you would have already).

2. Your animals love them more they love you.

3. You can brutally honest with each other. I mean really it's for their benefit.

4. There is no such thing as a normal snapchat between you and your bestfriend. It's almost a competition to see who can be uglier.

5. Popcorn and a movie night turned into popcorn and wine night which turned into just wine night which somehow ended in vodka shots and someone streaking.

6. You're always in sync with each other. Ladies, you know what I mean.

7. Showing up unannounced to harass them at work (and video document it, of course) is one of your favorite pastimes.

8. You may as well be sisters because their mom has basically adopted you at this point.

9. You know their significant other isn't good enough for them, but you play nice anyway.

10. You are all too familiar with their 3:00 am aggressive cuddling habits, and you have the eye-bags and bruises to prove it.

11. You make all these plans only to end up shamelessly bingeing on Game of Thrones and it's totally fine.

12. Parties just wouldn't be right if you didn't end up in the bathroom together talking about anything from the guy who just tried to hit on you, to what you're going to name your first kid (which clearly they will be the godmother to).

13. When it comes down to it, you would literally do anything for each other (as long as they spot your coffee the next day).

14. They've seen you at your best and at your worst, and they still stick around. You should really buy them a "thank you card."

15. And last but not least, they know you better than anyone. Seriously, it's like you share a brain or something. They're the first person you go to for advice, and you would trust them with your life, (and also to not judge your questionable dance moves).

It really is like they say, friends are the family we get to choose. You may fight like sisters, but you'll always be by each others side through thick and thin, no matter what, and 'till death do us part.