1) Facebook is indeed a global surveillance agency
I'm not so obsessed about privacy, I'm concerned, however. Facebook is explicitly selling users' data. In the past, Facebook did many dishonest deeds which is a clear signal for everyone to stop trusting it.
2) Facebook is not a real platform for social media
Many people think that Facebook is the sole and the most professional service for social media. But the reality shows there are way too many alternatives for Facebook, centralized, federated, and peer-to-peer networks. The mechanism of Facebook is stupid, what shocks me actually is the huge user base that Facebook enjoys.
3) Facebook is becoming a suitable host for negative ideas
Negatively-acting people are everywhere, but in Facebook, they find the easiest way to express themselves, and hurt other people. Racism, sexism, religious-based hate speech is flooding over the feed. This is unaccepted even in Facebook's so-called community guidelines, but Facebook is silent.
4) Very popular in my country!
Although this may sound a non-real reason for a while. But yes, it's been one of my main reasons to quit Facebook, for a long time. Facebook is popular in my country, and I don't like to see people around me in my digital life, especially when they misuse the services for their shitty purposes.
5) Not suitable for me
Facebook is meant for families and friends. But rethink about it; you can see your family in your real life, why you have to do so in the digital life too? Because of Facebook mechanism of friendships, I find it hard to express myself or to discuss people in large communities. Twitter is the best for microblogging and is very efficient for the people who want to express their ideas (like me), and Reddit enjoys massive communities and its mechanism is better to share materials with others.
7) I really hate Facebook
I admit I used Facebook intensively for many years, but it doesn't mean I liked it. I hate Facebook because they blocked my account twice for unclear reasons. Until now, they haven't allowed me to put my primary email on my profile, it is blocked. Facebook is very rude to its users, so why not switch to a more friendly platform? You should! Now!
My Facebook account used to be at: (Don't try getting into!)
If you knew me from Facebook, you can still contact me via other platforms. (see the home page.)