Having a sister makes finding a best friend virtually impossible. This has nothing to do with the quality of the people in your life, it's just simply that no friendship will ever compare to the friendship you have been lucky enough to grow up with. Being able to have a sister, and be a sister, will changed the way you look at friendships (even on the bad days).

1. Your sister was there before you ever asked her to be, and she won't be leaving.

Over the years friendships have come and gone, but she has always stayed by your side.

2. You never have to go back and explain that awkward moment when you vomited in front of your ninth grade crush.

She was there and remembers it. I mean who actually knows you better than the person you’ve spent practically everyday with for most (or all) of your life?

3. She adds a unique perspective to your life.

Most friends are drawn to each other because they have things in common, whether it's a sport, sorority, or job. But sisters might be complete opposites -- and that's okay. You didn't need to be drawn to her for any reason, you were just given her. You don't need similarities for conversation starters, you guys understand that you're two totally different people and it works for you. Sometimes you need her to tell you that your car smells like dirty laundry, and sometimes she needs you to tell her that dress isn't as cute as she thinks.

4. She is the only person who is able to annoy you to your breaking point.

But all is forgiven by the next morning. You may say awful things to each other in the heat of the moment, but it goes without saying that you didn't mean any of it. By tomorrow anything said won't mean a thing.

5. Your sister knows things about you no one else does, and vice-versa.

Whether she keeps your most serious secrets, or just doesn't broadcast over social media that you haven't gotten left the house in two days, just ate your third bowl of ice cream, and are currently crying while watching "The Notebook," you know you can trust her with anything.

6. No one will ever understand the frustration your parents can cause besides her.

You can spend hours venting to her about how they're ruining your life (and she'll understand when your pity-party is over by tomorrow morning). You both went through the same traumatic experience of learning to drive with Dad in the passenger seat and understand how irritating it is to wake up to a chore list from Mom.

7. She is the only one who will understand the bond you have with your parents.

None of your other friends want to hear about the inside joke you have with your family or understand why you decided to stay home on a Friday night to watch Netflix with them.

8. You’ve been sharing closets for so long that your styles have merged into one.

Who knows the amount of money you’ve saved by trading and borrowing from each other.

9. There's really no holding back the truth when it comes to her.

Want to know if that dress makes you look fat? Ask her. Does your makeup make you look clownish instead of fabulous? She'll be sure to let you know. Brutal honestly is had to get from friends, but she knows that the truth will help you way more than playing on the safe side.

10. She has seen you at your worst and still loves you.

The awkward middle school days filled with gel scrunched hair, Bermuda shorts, and too much eyeliner? She was still proud to be seen with you (well, maybe not proud, but she did it). Those post-break up weeks when you lived in sweatpants, ate way too much junk food, and sometimes didn't even look human? She didn't make you feel guilty for being down, she was there to raise you up.

11. You were given a built in maid-of-honor.

You never have to worry about which friend you will put this responsibility on, because you promised her the position back in middle school. Plus she is probably the only person who cares about the wedding and making everything perfect as much as you do (even more than the groom, I'm sure).

12. You have your own ways of communicating.

She is the only person who a 'K' text message is acceptable from and there's no guilt when you call her 10 times in a row until she answers. A lot of times words aren't even needed because the simple glance from across the room can get your message across.

13. Due to years of grocery shopping with Mom, you are both fully aware of each others favorite snacks.

This means you know exactly what food to bribe her with and you already know not to eat that last Oreos, but you probably will anyways.

14. She will naturally hate anyone who has screwed you over.

The friend who backstabbed you or any boy who hurt you, no explanation needed she already hates them for you.

15. She knows everything that’s going on in your life before you’ve even told her -- because she stalks your social media on an hourly basis.

She’s already warned your parents about the tweets about what a jerk that guy is, that way no one is surprised when you come home in a bad mood.

16. Your morals and values are probably similar, if not identical.

Growing up with the same parents shapes a person a lot more than you would think. Not everyone will understand or agree with your way of life, but you sister does. No one can always be perfect, but your sister is there to remind you of who you are. You hold each other to a higher standard, because at the end of the day you just want her to be the best version of herself.

17. She'll never let you forget your worth.

She wants nothing but the best for you and doesn't let you settle for anything less.

Being best friends with your sister isn't always easy, but it is easy to understand why she's your best friend.