You get talking. You chat about whatever brought you together that day, and whatever common background you have and whatever common knowledge you have of each other. As you talk to them, you start to think "wow, this person is actually kind of cool", or "huh, this person is kind of nice". You feel a connection, a kinship, a desire to keep talking even after that final bell has rung or the final project has been handed in. You have a want, a desire for more of this newly discovered person.
You friendship stays a little while in this embryonic stage, developing, incubating, maturing. You find out that you have common interests--a mutual hatred for a certain teacher, a mutual love for a certain TV show, or a mutual passion for a certain hobby. When you see this person outside your little bubble, you smile, then stop to talk to them. You start joking with them, playfully making fun of them. You've gained that first level of trust. Your friendship has grown from its toddler stage to its child stage.
Then, inevitably, comes the day when you invite the other person to do something, outside of the place that you meet, for no other reason than you want to spend time together. Or maybe they invite you. Either way, you find yourself getting to know them in new ways--seeing what their room looks like, meeting their siblings, experiencing the other parts of their world. You respond in kind, inviting them into your world, giving over a little bit more of yourself, trusting them to hold on to it, and not break it. With this knowledge and this trust, your friendship enters the teenage stage. You have to be careful here. It's equally parts exhilarating as it is challenging. This is the stage where the other person starts to change who you are. Most people forget most of their childhood memories; no one fails to remember their teen years. It's the point of no return, when you go from being casual friends, to real friends, from just a name, a quick "hey, we had fun times" to a "you meant a lot to me, I'll never forget you".
This is the point when you start calling this person you're friend without any hesitation. It's no long a question, but a fact. It is from this point that all other points blossom. You experience all the teenage rights of passage. You meet their parents, maybe even their extended family. You run after them when they go crying to the bathroom. You make them laugh so hard they cry.
Slowly but surely, you get to know this person, in all the big and small ways. You get to know their favourite colour and the route to their house and their family drama and every other little detail that makes them who they are. More importantly, you start to care about these details. The real marking of this stage is that moment when you start to care about this person not just in relation to you and your friendship, but just as themselves. You store every detail they tell you, drawing a map of their life in your head, sure to never get lost. When you load pictures from your camera, you save the ones with you, the ones with the both of you, and the ones of them alone. You decide that this person is going to be important to you, a part of you. It's a big decision, and you don't always realize it while your making it. But once you do, you'll never forget it.
Eventually, your friendship begins to experience some growing pains. It can take two months or ten. But eventually, it will happen. You grow past the adolescent stage, and things become so much harder. When you make mistakes, people are less forgiving. More is expected of you. Before, you were that person that ran after them into the bathroom. Now you're the person who skips the rest of the next class to hand them tissues, and then meets up with them after school and makes them tell you the rest of the story. Their pain becomes your pain. It becomes so familiar to you that you recognize it on their face before they've even acknowledged it. Sometimes, you're the cause of that pain. Sometimes, you don't know how to fix that.
You've now reached the final level of your friendship. This one can last five months, five years, or five decades. You now know everything there is to know about this person. You can anticipate what they're going to say, how they're going to react, and how you are going to deal with each and every one of these things. In many ways, you know them better than they know themselves. At the beginning of a friendship the other person shows you their strengths. By this final point, you not only know their weaknesses, but you've accepted them, come to love them.
Supposedly, you friendship could stay forever at this final level. But none of mine ever have. Many of mine have never even reached that level. Some get stuck in the embryonic stage or the toddler stage. Many only make it to the child stage. A select few survive until the teen years. Only one or two have ever reach adulthood. But even those have suffered early deaths. Friendships blossom because of proximity. And so they die when it's taken away. Even if you think you could never lose this person, can never imagine living without his person, you can still lose them. You may not think it now and you may never want to believe it, but it's possible.
I know. I have lost every friend I have ever had. And I'm about to lose a bunch more, when I graduate in two months. The people who make up my life right now, the people I see every day, will journey with me into the next stage of friendship. Before it was all about moving forward, going up levels. Now, as everyone moves forward to their separate futures, it's about moving onward, but not upward. Moving backwards instead of forwards. It's a natural progression that seems completely unnatural. You won't like it, but you won't be able to stop it.
You can't unknow the things you know. You will always remember that person who you were friends with, as they were for that moment in time when you were friends. But there will be new things that you won't be privy to. It can be quick, monumental, like when someone moves away to college or something. Or it can be slow, almost unnoticeable. One day you don't each lunch together. The next, you realize you haven't talked to each other in a whole day. Then a whole week. Then suddenly, you see them, and you talk to them, but they aren't them. You feel a little out of place, you can tell that something's off. This isn't your friend, but some weird impostor. You go searching, digging for the real thing, but it's nowhere to be found.
That person was a part of you, and now they're gone. And so you have to relearn who you are, redefine yourself. It takes a very long time. It's like when they demolish a building. The reconstruction takes a long time to cover up what was once there. Except instead of creating a better building, you can only construct a newer one, that isn't so tall or strong, since its foundation was already so scared.
For a while, it'll seem like you can't go a day, can't take a breath, without that person, can't walk a block without stumbling upon the building. You'll find yourself walking toward it, even when you don't want to. Every little detail will remind you. Every thing you laughed at, cried about. Every foolish prank, every sill joke. But slowly, you'll learn to forget. You'll be a new person, and you'll have new memories. Then, one day, you'll be walking down the street in your new life, existing in your new neighbourhood, finding your way in a new city, when you'll pass the building once again. You'll blink twice, making sure it's actually real. You'll find it hard to believe that this person that has existed for so long in your head is actually more than a thought or an image, but a real life thing, taking up space, in front you. You may embrace them, just to make sure they're actually there.
It will amaze you how quickly you'll be able to enter the building once again. You thought you had lost this map, made yourself forget these directions. But they're still a distant part of you, ingrained in you. All those facts that you were eager to learn and then so desperate to forget come back into you conscience. You roam the halls together, feeling like you're at home after a particularly long vacation that you didn't much enjoy.
The words will come so easy. You no longer have things in common, but you have a common past. There's a part of you that is still that person, that person that they knew better than anyone. And there's a matching part of them that you never forgot. You talk endlessly over each other, trying to learn the new person who replaced the old person you loved so much. Time passes so quickly. But just as quickly, it stops. You run out of things to say. You step out of the bubble, step out of the building and go on walking; you remember that this person you're talking to isn't your friend. They're a new person. They're a stranger.
That is how a friendship begins, and that is how a friendship ends.