1. There is literally no such thing as an awkward silence. You either have a billion things you could talk about endlessly, or you can relax comfortably in the glorious quiet together without feeling the need to fill the space with exhausting small talk.
2. You understand the easiest ways to make each other happy – like you giving them the window seat on an airplane or them knowing exactly how you like your coffee without even having to ask.
3. You can regress into making obnoxious noises instead of using proper vocabulary, and they’ll still understand exactly what you’re trying to convey – that you’re tired, or hungry, or hangry, or any other possible emotion you could be experiencing.
4. Snapchat conversations are less concerned with sending cutesy pictures to each other and more concerned with who can make themselves look uglier using the filters.
5. You develop your own little weird, shared shorthand, to the point where you can have full-fledged conversations in public that will barely be understood by anyone except the two of you.
6. They know almost as much about your work life as you do, so when you complain that a coworker brought her smelly lunch again, they know exactly who (Karen) and what (deviled eggs) you’re talking about.
7. You can tell them when they’re annoying you without any fear that it will lead to a breakup, or even an argument.
8. You become experts at reading each other’s individual stages of drunkenness and knowing which behavior corresponds with the cue to go home.
9. And even better, you know each other’s hangover treatments, ranging from mild to ‘No, I’m actually dying.’
10. You are way past the point of eating politely in front of one another, and can dive headfirst into a pizza with no regrets.
11. You call each other ‘dude’ just as often as you call each other ‘honey’ or any other term of endearment.
12. You can read each other’s moods and are always capable of deciphering when you want to be left alone and when you’re in desperate need of company and human contact.
13. They’re always down to do the nerdy things with you that none of your other friends will do, like going to the midnight premiere of a movie nobody else likes besides you, or trying a Groupon offer that everybody else is shying away from.
14. Your feelings for them grow from simply being something you feel in your gut into something you feel in a more practical sense – seeing them as the type of person you could make huge life decisions with, like moving or buying a house or having a kid, rather than just someone you’re super ‘into.’
15. Even if they don’t understand your weird humor, they’ll always at least be able to laugh at the sound of you laughing, and vice versa.
16. You can whine to them as much as you like, while always trusting that they’ll either be a sounding board if you need it, or the one to tell you to suck it up if you’re being a baby.
17. You can make peace with the fact that some friendships will naturally come and go, because you’ll always have your number one confidant right by your side.