Having a sister may sometimes feel like a nuisance. After all, the two of you may find yourself constantly disputing and arguing about utter nonsense. Yet there is something so amazing about having a sister, something that makes your sister an irreplaceable person in your life.

1. Your sister is a lifelong friend.

There's that saying that you can't choose your family, but you can choose your friends. This being said, you're already stuck with your sister, so you might as well be friends.

2. You have two wardrobes.

Now, if you're lucky enough to be the same size as your sister, your closet space immediately doubles. Suddenly it's like a whole new world of clothes, but it still seems impossible to find something to wear. Also, where is your GUESS sweater?

3. She always has your back.

When you feel like trash or have your heart stomped on, she'll always be there for you to defend you until the end. Even in the moment it may seem harsh, you know she always has your back.

4. Your sister is there for you.

There are few people in your life who are willing to stick around and watch as you go through the stages of life. She's been there for your whole life, seen some of your worst downfalls and been there to celebrate your greatest achievements.

5. She loves you for all your flaws.

She knows that you can be extremely bossy at times and that you refuse to try sushi. However, she accepts you for it--even though she still may try to slip you some sushi when you aren't looking.

6. She knows your secrets.

With sisters there are no secrets. She is all too aware of that time you managed to break that upstairs window and tried to cover it up with duct tape (hey, she even tried to help you cover it up). But still, she knows your past and there's no way of hiding it.

7. She shares your weaknesses.

She knows that you are a sucker for chocolate and she is too. So we all know where all the chocolate in the house disappears to.

8. She knows your obsessions.

After listening to you for days playing Taylor Swift over and over again, she has finally had enough and is close to making your iPod disappear. Yet she still gives you Taylor's latest CD on your birthday.

9. Sisters are the best.

Your sister can drive you nuts and put you on the verge of insanity, yet somehow you can look past that. You know in the long run that you both love each other, no matter how often you fight and think that it will be impossible to go on with them. You know that it would be impossible to go on without them, for there is no one else who can hold that position as your sister.