Things you should never do on facebook.

1) DO NOT use a weak password

Given the wealth of information about you on facebook, there’s no reason not to use a strong password with a mix of capital letters and numbers.
2) DO NOT add people you don’t even know

It’s one thing to add an old friend and then never speak to them. It’s another to add anyone whose name you kind of vaguely sort of recognize. It’s like that old man in the pub who slaps everyone on the back as if they were old pals, when in actual fact he has no friends, largely because of this habit.
3) DO NOT accept friend invitations from people you don’t know

It’s one thing to complain about irritating people adding you on Facebook, but if you accept those invites, you’ve only got yourself to blame. If you scan through your Facebook friends list, you’ll doubtless find a handful of people in there you barely know. It’s a horrible realization – like when you suddenly realize your hand is resting on a knob of someone else’s chewing gum underneath a desk.
4) DO NOT write on a wall instead of communicating privately

The driving force behind the success of Facebook is… vanity. People love the idea that others are watching what they’re doing. Tell me this: for what reason would you invite someone to a private party by writing on their wall, other than to show off to all the people on their friends list who you don’t want to come? It just makes you look like a tit, so don’t do it.
5) DO NOT post anything on Facebook while you are drunk.

Have a little common sense. If you go out for a big one on Friday night, come back and sleep. Because when I call in sick at 9am, the last thing I want my boss to say is: “I’ve seen the pictures of you crawling in the gutter last night. I’m not amused or impressed, now get to work!”
6) DO NOT Upload photos to Facebook and deleting originals

Uploading photos to Facebook can be a very handy way of sharing your holiday snaps. But for the love of God, don’t lose your originals. Facebook is terrible at compressing and resizing images – it turns your 14MP panoramas into 14KB monstrosities. Facebook is not a suitable repository to store your precious photos!
7) DO NOT have your relationship status set to “It’s complicated”.

If your relationship is so f*** complicated that you have to identify it as such on your Facebook profile, get the hell off Facebook and go fix your relationship.
8) DO NOT add your boss to your Facebook.

The below picture explains reason.