There is no one on Earth able to inspire such feelings of affection, jealousy, competition and pride as only a sibling can. They irritate us, steal our Legos, steal our attention and somehow we still like them at the end of the day. It’s rare in human relationships to be able to get away with so much mischief and still be the object of so much endearment. But somehow, they do it.

Siblingship is quite a paradoxical relationship, given that siblings are, by nature, both our truest allies and our fiercest competitors. In a sense, they are a reflection of us: In genetics as well as in spirit, they tend to share the biological and environmental influences that define who we are. Though there may be a few minor differences, at the end of the day, they are essentially the closest thing to ourselves that we will ever find.

Evolutionarily, as is seen in other animals, siblings have always been an adversary in trying to claim parental resources and attention. We are, of course, not inclined to share with them — we fight over the last taquitos at the dinner table, shove them during backyard soccer and willfully try to outdo them in front of our parents. But with this competition comes a transformative experience. From the moment we lay our wondering eyes on them, they force us to realize that we are not, in fact, the center of the universe — that there’s a bigger or littler “me” out there, someone who presumably sees us as either an older confidant or a younger protege.

Despite the natural competition, whether in foot races or spitting contests, only a brother could remain friend number one for so long. Through all of the fistfights and property destruction, the means of forgiveness that only a sibling could employ or elicit is amazingly powerful, preventing us from ever holding a grudge.

Perhaps it’s because we know we’ll be stuck with them anyway and see them the next day. Or maybe it’s because we’re able to connect with them more than with anyone else — able to vicariously experience their pain and their happiness. Regardless, any kicking and scratching and the simmering silence that follows is inevitably broken by a resigned attempt to restart a conversation and sheepish grins on both sides.

As a result of this essentially unbreakable dynamic, this relationship is an interesting case study in power psychology. Younger siblings learn over time to endure the typically unbalanced hierarchy of strength, but look up to their older siblings over time, often emulating their affectations and opinions. Older siblings are more or less free to lord it over our younger counterparts and often exploit this. And yet they are so fiercely protective and so inseparably attached, ready to obliterate at a moment’s notice anyone other than themselves accused of harrassing their sibling.

Although I’m over two hundred miles away from my best friend, eternal tormentor and first legitimate ‘bro,’ we still share a special connection. I may not have always appreciated having a brother, but it is truly a wonderful and special privilege.