Sergio Carracedo 
Long answer (TL;DR):
I joined Facebook on December 31, 2008 (almost 10 years ago now) but for a while now it hasn’t provided me with what it used to—a way to connect and share interesting moments with my acquaintances, friends, and relatives; instead, it had become a massive multiple monologue.
I must say that every year around this time I had the habit of reviewing my contacts and shamelessly deleting those people with whom I hadn’t had contact on the platform itself (not a comment, not a like, not a chat in several months) since it doesn’t make much sense to be “linked” to a person with whom you don’t have even a minimum of interaction.
This had allowed me to keep my timeline quite tidy, avoiding as much as possible chain messages, “challenges”, fake news (hoax), and stupid things that repeated every so often: the one about repasteurized milk, the one about intellectual property of the content and photos you upload to Facebook, and so on. But lately, they already represented a high percentage of publications.
But what made me make the decision most is something that might seem trivial to many: The order of the timeline.
Yes, it might be nonsense to many, but for me, the fact that Facebook ordered posts according to its own criteria drove me crazy, because I would see the same post multiple times, and I didn’t know if what was “below” it was something I had already seen or not. It is more than clear that this makes you spend more time on the platform, which is Facebook’s main objective, or at least one of the main ones. And this isn’t paranoia or a conspiracy theory; the interest in ordering news according to Facebook’s criteria is significant. For example, in the web version, you can select to show “Most Recent,” but when you click on the Facebook logo to return, the timeline “forgets” this option. I installed an extension that added a parameter to the home timeline URL to force chronological order, but after a short while, Facebook started ignoring it.
In the mobile app, which is a resource hog (storage space, memory, battery), this sorting option wasn’t even possible in a simple way (without having to go through 5 menus).
So little by little, in a quite natural and non-traumatic way, I realized I was using it less, until one day I decided to uninstall the mobile app and log out of the web session.
I must say I considered deleting the account, but being a developer and having apps that use the Facebook API, it was going to be a hassle.
I have also downloaded all the data that Facebook theoretically has on me; you can check how to do it here https://es-es.facebook.com/help/131112897028467 and you can see for yourself how Facebook forgets nothing; any “friend” you had and deleted will still be there in a list of your relationships.
Am I encouraging you to leave Facebook too? Not at all, I simply wanted to share my point of view and my experience regarding this.
Don’t you miss it? No, I’m a Twitter hard-user, and to connect with family, friends, and colleagues, I use other methods.
In short, what has happened after leaving Facebook? Nothing bad, I haven’t lost friends (the real ones) or anything like that, people haven’t stopped talking to me, nor am I out of the loop without knowing the “latest news”.