Friendship- Moving on to better friends

Friendship is one of the most familiar & common of interpersonal bonds. Some people (I used to be a part of this group) feel that the ties of friendship are stronger than those of your own blood.
But what makes people who were at one point inseparable split apart?

There's a lot of reasons friendships can nullify over periods of time. It could be due to something such as distance, such as when young friends are separated by their families relocating.

Or perhaps you start to realize that a person's friendship is bringing you down or preventing you from being the person you want to be. For example, one of my old best friends who was also my first real roommate was Luke S. We became very close friends, and I still consider him a brother to this day even though we don't talk very often. When we lived together we were (being in our late teens/early 20s) in our wilder stage, and we would drink a lot and do things we shouldn't have been doing. Luke got married and had a kid and thus he realized he needed to snap out of that stage and started trying to focus on other things. But when we hung out, he had the urge to drink (more than usual) and do other things that weren't, in his opinion, morally acceptable. Eventually he decided to cut his association with me and although he never told me why, I eventually pieced together that the reason was because he felt like my friendship was having a negative impact on him. Not that this was my fault, because it wasn't- but it doesn't matter who's fault it was. The fact remains that when he was around me, he had urges to do things he didn't feel were right- Party, do drugs we used to do when we were younger, go looking for other girls etc.

Or it could be the opposite, instead of someone feeling like a friendship is having a negative effect on them, they might just find people who they enjoy to associate with more, and then invest time in those relationships instead of the current friendship. Maybe they don't want to invite you (the old friend) because they feel you would take attention off of them in their new group, maybe they fear their new friends would like you better. Or maybe they think your new friends would think you were nerdy, or bad association, or something else that would embarrass them so they never bring you around. This is the more selfish way a friendship dies, but the fact is we've all had people that we hung out with (usually when we were young) that we really only hung out with because A) we had nothing better to do sometimes and/or B) they were close/convenient association. Sometimes though your interests just plain change, and you find new friends who share your new interests or hobbies. There is nothing wrong with that, but personally I have always felt unless there is a real reason for not talking to an old friend (such as them bringing you into situations that are trouble) you should try to stay in touch with your old friends and at least see how they are doing. That can be hard because you may know that if you make contact with a person they will try to scold you for not hanging out with them, and hanging out with your new found friends more etc. Or maybe they will invite you to hang out and you know you really won't want to hang out, but you still just want to keep in touch. I still think it's best to try to keep in touch somehow, maybe email or myspace/facebook... shoot a message every month or so and ask how the person is doing.

Because when you move on to "better" friends, just like any other type of relationship, those friends may move on to someone "better" than you.