Meditation or Mediation?

So I drove back to work in silence today, at lunch. I guess I needed the meditation time. I'm not really sure what prompted it, other than the static of the radio, prior to turning on the Sirius, which was really annoying. So instead of turning on the Sirius, I turned the radio off. And the 10 - 15 minutes i spent in silence, trying to reason out some of the things that have been bothering me so much lately. The first question that pops into my head is, "Why do people want to stop being friends with someone?" In other words, what is it that makes a person decide, "Hey, I don't want to associate with this person anymore."
My sis-in-law and I have discussed this before, and she has confessed to "downgrading" someone if their behavior or actions are getting on her nerves. In other words, she won't hang out with them as much. But she doesn't completely cut off all ties or anything drastic. And the person we were talking about at the time has since been 'upgraded' again. But what I am referring to is when people 'dump' a friend, never having any contact with them again whatsoever. It's obviously hurtful. But in my mind, I'm thinking that the only thing that would cause me to do that to someone else is something irreparable, or quite severe. Then I think back on people who have done this to me, and I can't think of a single example of something that I've done that would fall into this category. I've never committed any crimes, never made a pass at someone's significant other, never done anything deliberatley destructive, and so on.
So I'm still driving and I start to think that maybe the question isn't about other people, but about me. Why do I have the need to ahve a lot of friends, or a large social group? Setting aside the anthropological discussion, I realize peole are social creatures, pack animals and such. But I'm not talking about acquaintances. There's something at my very core that requires people that, in the past, I've referred to as the family by choice. Those people who you are pretty close to, as close as family, but it's by choice, not by birth or marriage. Am I expecting too much by asking the universe for those people in my life? Am I incorrectly perceiving other people as having those relationships? Is it necessary to my survival to have those people? And why do I take it so very personally when I am 'dumped?'
I should preface that by adding that I try to apply The Four Agreements to my life as often as possible. I notice improvements in my life when I do. And at the very core of the Agreements, and the first and foremost Agreement is "Do not take anything personally." Read the book for deeper discussions, but the long and short of it is this: Nothing that anybody does to you is because of you. What they do is because of their own perceptions, their own personalities, their own life. Not you.
I had a revelation after I start thinking about how sad it is that our friends Ross and Carol will most likely be moving to Qatar in the next few months. Being smack dab in the middle of the Persian Gulf, surrounded by American-hating countries isn't very conducive to us visiting them very often. So it's very likely we won't see much of them anymore. Does this make me sad? Of course! By description, we practically aren't going to be friends with them anymore. We won't get to talk to them very often, and won't see them much, if at all. But of course we're still friends. Down the road, if we see them, we can pick up where we left off. And I'm not taking their move personally at all. I could, of course. Jim and I could twist it around to be about us. They're moving to the middle East because they don't want to be friends with us anymore.

Now, I realize this is patently absurd.

But when someone makes another type of decision that affects their relationship with you, such as a personality clash, it becomes incredibly easy to internalize it, take it to heart. So I am confused with how I can get around this. It hurts, and I wish it didn't happen. But there's not a lot I can do about it. Should I change my personality? Well, then they don't like me for *me*. And if I try to apply this same example with Ross and Carol, us changing anything (realistically) isn't going to change their decision to move. So how do I come to grips with being dumped? Why does it constantly haunt me? Last week I was laying in bed, trying to sleep and instead this shit is going through my head, and I end up having a crying jag til about 1:30 in the morning. How much is too much? What is a normal amount of sorrow, and what is depression?

So to end, I'd like to know what it is that would cause you, daer reader, to completely close someone out of your life. And my sincerest wish, though we may never meet, is that nobody ever does this to you.