Has anyone ever unfriended you without explanation? Did you ask why? Have you ever deleted someone from your friend list without saying why?
Sure, I've been un-friended, but I never worried about why. I just figured that they weren't interested in the subject matter of the blog (which has drifted from politics/opinion to reviews and lots of Buffy stuff). I've also un-friended from pages which never seemed to be updated and which also hadn't friended back, because it seems like that is a good hint that maybe the person isn't on LJ anymore... or they're just drifters... either way... it didn't appear that they actively used the service. I've never bothered to send a notice that they were being un-friended either, because I figured they weren't likely to care.