1. When you're rummaging through her closet and you hear her coming up the stairs.

2. When all of your guy friends always say: "Your sister's hot."

3. When she all of a sudden turns into your mom and you're like, please stop?

4. When you see her out in public wearing ALL of your clothes.

5. When you have to "share" the bathroom.

6. When your parents let her do something, but not you.

7. Or, when your parents take her side.

8. When she goes shopping and you know this means you'll essentially get new clothes too (since you can steal hers).

9. When you can always tell who showered last...

10. When (even as adults) she tells on you to your parents.

11. When she's the only person who won't make fun of you for asking stupid (but necessary) life questions at any moment in the day.

12. Whenever you're at boring family functions and you always have a pal.

13. When sometimes you're convinced she's actually the much cooler, more fun sister.

14. When you both get in trouble, but it isn't so bad because at least you're in trouble together.

15. When you realize you would not be the same person today without her.