Throughout our lifetime we will meet tons of new people, and make tons of new friends. We all have our closest friends, our best friends, our 'person.' But, anyone who was lucky enough to get a sister knows that they are the best friend of all. There are so many reasons that a sister is the best friend you'll ever have, but listing them all would take too long and probably be impossible given the list is never ending. So here are the 21 main reasons that sisters are the greatest best friend of all, and 21 reasons us girls with sisters are the luckiest of them all.

1.Sisters don't have a choice in whether or not they want to be your friend, they were literally born to be your friend.

2. During a fight your sister can only mildly insult you because you two have the same DNA makeup, so if she insulted your looks she'd basically be insulting herself at the same time.

3. You and your sister can have a top-of-the-lungs screaming match, but you know that you'll both be over it by the next day.

4. Your sister will hate anyone you tell her to, and you'll do the same for her.

5. Your sister will be mean to you all the time, but you know as soon as someone else says something bad about you she'll shut them down immediately.

6. Your sister has a sixth sense when it comes to your boyfriends, and will be brutally honest if she thinks he's not right for you.

7. Similarly, your sister also has a sixth sense when it comes to your friends, and will always know which friends are real ones to you, and which ones are just super fake.

8. Even if she doesn't know about it all the time, your sister's closet is the perfect place to look when you seem to hate every article of clothing you own one night.

9. You don't care if there's nothing going on during the weekends because you're both more than happy staying in baking and watching movies with your sister.

10. Your sister is just as weird as you are (again, same DNA), so she won't look at you strange when you doing something that would be weird to outsiders.

11. If your parents are getting on your nerves you can always complain to your sister because she actually understands what you're talking about, unlike just a regular friend would.

12. You have a predetermined bridesmaid for your future wedding, and you know you'll be one in hers, so you don't have to worry about never being asked to be part of a wedding party.

13. Your sister won't ever make up an excuse as to why she can't go to lunch with you because she knows you'll call out her B.S. if she ever tried.

14. You know that you can go to your sister with all of your secrets, and don't have to worry about her spreading it around to other people.

15. You never have to worry about you and your sister drifting apart, and you know that no matter how long it's been since you've seen each other you'll always pick up right where you left off.

16. Your sister is always brutally honest, and she'll always tell you if your outfit makes you look fat, or if your new haircut isn't the greatest one you've ever got.

17. You never will have to worry about finding a babysitter when you eventually have kids because she'll be your go-to, and even better is that she isn't allowed to quit if your kids turn out to be unruly.

18. No matter who you were with, where you are, or what you were doing, your sister will always be willing to bail you out of trouble.

19. If your parents happen to catch you in a lie you know that your sister will always be your alibi and cover for you, especially because you are always hers, too.

20. When the time comes, if you're the younger sister you never have to worry about getting a fake I.D. in college because it's an unspoken rule that the older sister gives you hers.

21. Your sister is always wanting the best for you, and will always do anything she can to help you in anyway possible.