Agh, this thread is just full of people boasting about their immunity to interest in Facebook. Congratulations, you're fantastic, oh that we could all be as enlightened as you.
Personally, I find that Facebook has become my address book - while I still text people I see every day, Messenger group chats are often used instead. Plus the voice and video calls have been a great way to keep up with people further afield. Yes, Skype exists, but Facebook is easier - which is huge with older relatives.
That said, this study doesn't surprise me. In terms of public posts everyone projects their "best life", so you're browsing through a catalogue of amazing experiences while you sit at home feeling a little fat.
I'm not sure what the answer to that is. Some say Snapchat is a much better place for people to be their true selves - I can believe it.