1. The competitive-but-in-a-friendly-way one:
gifsoup.com
You always end up laughing after one of you cheats.
2. The one who loves to gossip as much as you do:
Via gifrific.com
Because somebody's got to know everything, right?
3. The genius who's always correcting you:
herrohayley.tumblr.com
Deep down, you kind of appreciate it.
4. The one who will help you manage crush drama:
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5. The one with whom you never have to write full sentences:

A. Nyst
6. The one who makes you laugh until you collapse:
youtube.com / Via gifrific.com
7. The one who always tells you the truth, even when it hurts:
NBC / Via gifsoup.com
8. The one who will break you out of your shell:
crash2thestarlight.tumblr.com
We all need a little encouragement, and this friend is yours.
9. The Snapchat queen:
vine.co / Via perezhilton.tumblr.com
#selfiesaremylife
10. The sporty one who pushes you to run the eight-minute mile:
gifbin.com
She's a motivational master.
11. The one who took all the notes in class so you didn’t have to:
20th Century Fox Television / Via blessedbeyoundmeasure15.tumblr.com
12. The one you have all the inside jokes with:
13. The one who’s always down for a good night out:
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OR IN.
14. The one you know you can always do stupid things with:
youtube.com / Via zoella.tumblr.com
15. The one you don’t see that often, but with whom you always pick up where you left off:
16. And of course, the BFF:

Manannan Images / (CC BY http://2.0) / Via Flickr: 125402076@N03
The one you can trust through thick and thin — she's your boo.