As a kid, I was told that would have different groups of friends as I would grow up. I couldn't understand how it could happen to me but as I grew up my interest changed and so did my friends.
What I didn't realize, in my younger years, is that a lot of what we had in common was the experiences we shared in school. We attended the same classes, we partnered up for projects, we liked the same sort of things.
Once school was over, and we went our separate ways, we all grew into new people that slowly left our past behind including our relationships.
We're all busy doing other things and over a period of 15 years we slowly drifted apart to the point that I don't think we would recognize each other. They surely wouldn't recognize me as not much remain of the person that I was - I've grown just from a year ago.
I just kind of accepted this as a part of life. Have you been able to keep up with your friends after 20 some years out of school?