Think back to your last first date. Were you 100 percent yourself? Probably not, and that's totally normal. When you're in the midst of courtship, you're trying to make the best impression. But the deeper you fall into a relationship, the more comfortable you become around that person, and the more that the "real you" comes out to play. The most lovable things about people are their little quirks and eccentricities. When your partner is your best friend, you officially feel safe enough to expose yourself, which is totally freeing and will only bring you guys closer.

If you get a promotion, hear that a family member is sick, or see something really bizarre in the grocery store, you immediately pick up the phone to tell your partner. Whenever you receive news — whether good or bad — you want to share it with your SO. You may even feel the need to keep them updated on all of the mundane things that happen during the course of the day. You want them to be a part of every aspect of your life, because you know they care about you enough to want to hear the news.

Like real, hearty, belly laughter. You share a sense of humor, you make each other crack-up, and you're all-around happy in each other's company. Your SO know what will make you laugh at things that no one else would find funny, and you know how to get them giggling with just one word or look.

You have the same favorite burrito joint, you like the same movies, you have the same dream vacation. If one partner really likes elephants, it won't be long before the other person starts picking up elephant trinkets and sending elephant themed greeting cards as well. When you're in a relationship with your best friend, the fun stuff that one of you likes slowly melds into a shared interest between the two of you.

When you're new to a relationship, it's normal to play it safe and stick to dinner and a movie or getting drinks at a local bar. But when you've been dating for a while, your dates start to look less and less like the dates you see in movies. Maybe you go on a long drive to nowhere, hit up the aquarium, or cook a five course meal in your PJs. Anything can become a date, and most of the time you don't even think of it as a date. You're just spending time with your best friend, so it doesn't even matter what you're doing.

When you're on your best behavior, you'll tip-toe around unnecessary conflict and continue to exist in a honeymoon mindset. But when your partner is also your best friend, this is not the case. You will wrestle each over for the last piece of pie, and you might even leave passive aggressive Post-It notes in the bathroom asking them to clean up after themselves. You can call each other out when someone is totally in the wrong. But what's great about this state of comfort is that these little, insignificant disagreements don't really matter. You can argue over who gets control of the remote without worrying that it will put your relationship on the rocks, which is pretty refreshing.

When you're dating your best friend, you're ensconced in each others' lives. You have mutual friends, you know (and like) each others' families, and you know exactly what they're talking about when they say "the Chinese place down the street." You don't live two separate lives that orbit around each other — you share the same places and people; you live a lives that intersect.

You don't need to be entertained by external forces when you're together. Lying on the couch and vegging out is a perfectly acceptable way to spend a night together. You're comfortable with silence, and you're okay doing your own thing when you're in each other's company. You can be together doing a whole lot of nothing and be perfectly content. Maybe even happy.

There are some things only your best friends know, and consequently love, about you. When you know your partner's complicated coffee order without hesitation or you can easily list their guilty pleasures, you are officially in best buddy territory. Knowing these things makes you closer to each other, which only makes you fall deeper in love.

Courtship is full of grand gestures — bouquets, fancy dinners, elaborate two month anniversary gifts. People tend to think these romantic overtures die out once you're in the thick of a relationship. But they don't; they just change. You do smaller things for things, but things you know they'll truly appreciate. Maybe you steam their shirts for them when they're in the middle of a busy week. Maybe they pick you up a box of your favorite chocolates just because. The nice things you do for each other might not seem like much to an outsider, but who cares about an outsider? They're thoughtful and personal, which makes them all the more special.

When offered the choice between drinks with a coworker or Netflix and Chill with your SO, nine times out of 10 you choose your partner. This isn't to say that you don't have other friends or a life outside of your relationship, just that when you have the option, you'd almost always rather be with them. They're your other half, your best friend, and you can't think of anyone you'd rather spend a day with.

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