Define-ding Friendship

My friend Kate turns 18 in two weeks and has come up with the idea of hosting a small get-together of her closest friends on the eve of her birthday. 

I suggested that she make a list of all her friends, so no one gets left out, swears eternal revenge, and curses her future child - who one day touches the pointy tip of a magic spindle and sleeps for millions of days, until Prince Charming, with his blindingly white smile, kisses her and concludes her early life to the much-aspired and often elusive stage of happily ever after.

I handed her a post-it, on which to write out a couple of names to invite. Instead, she grabbed my A4 pad.

As she began to write down the names of her closest and dearest friends, watching the list grow and grow until it no longer looks like an invitation list but more like the phone directory, made me question (internally), just how close a friend she is with all these people. 

Is it humanly possible to have so many friends? How can one person juggle school, appearance and weight, and at the same time maintain friendships with so many people? Maybe our definitions of what a friend is, are completely different. Maybe she's just not very selective with her friends - calling the guy, whose mobile phone she once had to use when she ran out of credit, her friend. Or maybe I am just an elitist snob who is too uptight with labelling people as friends.

What exactly defines a friendship? Is this a question that has no concrete answer, like the meaning of life, or how long should I leave the hair conditioner on?

My volatile theory seems to be that a friendship, just like all relationships, is defined by another. X and I must be relatively friends because, compared to my relationship with Y, we get along well. Is friendship something relative?

Regrettably, I had asked this question to my friend Margaret, to which she shrugged her shoulders and said, "Did you know that Naomi Campbell and Stefano Pilati are both gonna be on the cover of August's issue of i-D?" Were we even friends? Or are we just people who hang around together, sharing similar tastes in fashion, music and the like?

And what exactly are the ingredients to a friendship? Is it platonic affection and altruism (in which case, I have few friends)? Is it a shared, common interest in something (in which case, I have a lot)? Or is it all of those (in which case, I have one or two)? 

Whether I answer this philosophical sudoku or not, the small get-together of a hundred thousand people will go ahead.

I end this post scratching my head. Not in a I-have-headlice-manner, but in a confused one.