Here is a priceless example of why it’s really important to remember who you add on facebook.
Maybe just as important is to remember why you use Facebook/linkedin/Twitter/Whatevr.
If you use it for work or professional networking, don’t add “Stinky Dave” from uni and certainly don’t comment on his video of his dog trying to have sex with his neighbour’s cat.
Facebook does have settings to allow you do choose which content you share with whom. But it’s complicated and tricky to stay on top of it.
My advice is to use one SocNet for friends and one for work. And never the twain shall meet.