I'd think facebook is scsry for me because i myself am a heavy user of it and almost all my apps are synced up to it so I don't need to enter my passwords all the time. That being said, there is alot of pertinent dta there about me. Although this data in itself is not important, but combined with others, it's dangerous.
You better watch out bro! You are being monitored and your data is being collected across board. 
Just kidding though! However, it is still something you always have to take into consideration when it comes to data and with some of the news we have heard in the past about Facebook selling the user's data to highest bidders which to me is highly unethical. Sure, we can say we share data everywhere and as long as we are on the internet, data are prone to be leaked sometimes, if it gets into the wrong hands, but whichever way, in this case, what can we really do about it?