1.
Keeping each other's secrets no matter how juicy the gossip is.
2.
Reading each other's mood without having to ask how they're doing.
3.
Patiently listening when one of you is in a state and needs to vent.
4.
Playing it cool when someone calls your best friend their best friend.
5.
Conveying a whole bunch of thoughts just through one look.
6.
Analysing text messages from each other's potential dates as if you're going to be tested on it.
7.
Keeping each other up to date with every single moment of your day.
8.
Getting over arguments and letting go of grudges.
9.
Giving each other some honesty when needed, without being a dick.
10.
Knowing what to do when one of you needs some cheering up.
11.
Sharing your possessions without any hesitation.
12.
And not allowing each other to put yourselves down.
13.
Defending one another from anyone who says a bad word against them.
14.
Writing an essay in each other's birthday cards every year without repeating the same points.
15.
Making room for dessert even when you don't want it, because your best friend does.
16.
Being each other's wingperson on a night out.
17.
Hating anyone your best friend hates, automatically and without question.
18.
Enjoying each other's company without talking or really doing anything.
19.
Refraining from watching the show you're both obsessed with without the other one present.
20.
Knowing the quickest way to make each other laugh in a serious situation.
21.
And always making sure to celebrate all of each other's successes.