Whether you met her in pre-K or fifth grade, you will never forget your childhood best friend.

Not only did she teach you that the brown M&M's are the best (because brown means extra chocolate), but she taught and experienced so much more with you.

Here are nine things you should thank your childhood best friend for, but, let's face it, with a friendship like yours, this list could be as long as your friendship.

1. For being your friend in the first place

Little did she know how scared and alone you felt on that first day of school, and that her coming up to you and saying "hi" was an answer to your prayers. Also, it was the beginning of a lifelong friendship.

You will be forever grateful for the meet-cute with your best friend, and it's probably a good idea to let her know.

2. Going along with your crazy shenanigans

Kids tend to get in trouble, and lucky for you every time you had a "great" idea that invariably ended badly, your best friend was right there beside you.

Not every decision was a good decision, but at least you didn't have to face it alone.

3. The endless fun and laughter

When you were with your BFF, one thing was for sure: Not a single moment was a dull one.

You probably have too many inside jokes to even count, and there were many times you both spent laughing way into the wee hours.

No one could make you laugh like she could.

4. For always saying sorry/forgiving you quickly

If there's anyone who knows you aren't perfect, it's your best friend, and you love that she loves you despite these imperfections.

Looking back, you are probably so grateful for the many times she was able to forgive you quickly for your childhood foibles, as well as be quick to apologize for hers.

5. Standing up to each other's haters

Not everyone understood you the way that she did and vice versa, and sometimes people were really mean about it.

Lucky for you your best pal was always around to come to your defense, and you also made sure to always have her back.

It was always nice to have someone in your corner, and you have her to thank for that.

6. Becoming a part of her family and her becoming a part of yours

If you weren't at her house, she was at your house. This meant that her family pretty much became your family and same with yours for her.

You loved that you could walk into her house without even knocking, and when you walked in it felt exactly like home.

7. Letting you make mistakes but also telling you like it is

The one thing you could count on your best friend for was her honesty, and there were many times you needed it - it averted more than a few possible disasters.

At the same time, when you were determined to make a mistake, she stood by you even though she knew it would end badly.

8. Keeping your deepest, darkest secrets

She's seen it all - the good, the bad and the very bad - but lucky for you, there is no one you trust more with all your secrets than your best friend.

Growing up you felt so lucky to be able to always have someone to confide in, and even now looking back, you are still grateful for that.

9. The unconditional love

The reason you think so fondly of your childhood best friend is she was probably the first person to teach you the true meaning of true friendship, and that is really unconditional love.

You will forever be grateful for your childhood best friend, and let's hope on the happy occasion you get to see her again, this list will provide some reasons to profusely thank her.

Sometimes all it takes is a friend to change your life for the better, as is shown in the upcoming movie adaptation of the novel "Wonder" where 10-year-old Auggie is learning to navigate friendships in a new school where people have a hard time accepting him due to his facial deformity. "Wonder" is the new drama by Stephen Chbosky, starring Jacob Tremblay, Julia Roberts and Owen Wilson, out in theaters Nov. 17.