What's the difference between people that you've had for friends since you were 4, and those that have drifted away?
Honestly though, that's what life is about. People come and go, and the ones that are worth hanging on to you stay friends. Not by sticking to them like glue, but just through fate and willingness.
I've had many friends in my life time, some for a long time, some for a short time. The ones that have drifted away, it was always for a reason, either with me or with them, but the outcome was the same. Other friends I'm closer to know more than ever, but even then I know it won't last, so I'm going to make the most of it now.
I remember some conversations with a good friend of mine, we told each other that we would be friends forever.
But life had other plans, our lives have changed so much that we've just drifted apart over the last two years. I don't begrudge it though, it's just part of life, but I do miss the great friendship.
Perhaps just give up the notion that you have to be friends with people forever, and just enjoy them when you can. People
*will* exit your life, time to time. The important thing is that you know this deep down and can let go of them with love, compassion and freedom, as well as fully enjoying the rare time you have together.
In fact: is there anyone in your life right now you could be closer to?