Prompted (nudged is probably more accurate) by a post from William Carleton, I finally deleted my Facebook account. I had been thinking about doing so forever, but just never got around to doing it.
Numerous others have written about why they "left Facebook" (see, e.g., Steve Coll: "Leaving Facebookistan"), and I'm skeptical that I have anything to add to the mix, but finally deleting my account feels like a very small (tiny pebble-size) weight off of my shoulders. I had approximately 200 friends, and about 100 friend requests pending, but I just never ended up logging in to Facebook. I'd say I logged in once per month at most. (I should note that I still use Instagram and couldn't get myself to delete my account there.)
Facebook's privacy settings were not the easiest to figure out and changed frequently. In particular, it seemed difficult to figure out how to control distribution of your posts, who could comment on your posts, and what account to post from if you have multiple accounts. I controlled my group of friends pretty carefully and they are all run-of-the-mill, mainstream, law abiding citizens (one or two exceptions notwithstanding), but I just couldn't shake the sense of paranoia that something could go wrong with my Facebook account. I never bothered with Facebook's mobile app. From what I heard, it wasn't very easy to use, and always seemed like the true grey area as far as user privacy was concerned. But what truly prompted me to leave was a feeling similar to the sentiment expressed by Eryn Loeb in this 2010 article from the Awl ("My Former Best Friend's Wedding"). I'd state Loeb's point in slightly different terms: why mess with the natural order of things when it comes to your past friendships and relationships?
Try as I might, I couldn't think of a good reason to do so.