People suck on facebook

So it happened again this morning.  I realized someone had defriended me on Facebook.  And it wasn't one of those Facebook "friends" that you don't really know too well either.  I'm pretty sure that this has happened at least ten times  in the past year.  For some reason, today, I was sort of crushed by it.  I wasn't close with any of the people who defriended me, but they were more than acquaintances.  Does this happen to everybody? I usually feel like I have no idea why I got defriended so I often take it personally.