Yeah, there are times where I lost contact with former friends/acquaintances, whether it be because I wasn't good at keeping contact or suddenly someone else didn't want to contact me anymore. For the latter, even though I might have a feeling our friendship wasn't going to last, it still made me sad with me thinking perhaps I did something wrong.
One of the biggest things I'm guilty of in my life is not really keeping in touch with people. This applies to every single job I've had, this applies to my former high school classmates who I never speak with anymore, so on and so forth. It's not like I intentionally don't want to talk to them, it's just that most of the time I'm busy, and other times I just don't know what to say to them. I want to put up more of a conversation than just "hey" and I think that's where my mind kind of has a brain fart everytime the thought of talking to an old friend pops up.
I can relate to this. I too sometimes have a hard time making conversation whenever I meet an old friend. Maybe it's because I'm convinced we probably don't have much in common anymore and are now living different lives.