I used to use Facebook awhile back. I thought it was good at the time. There were quite a few things to do, like upload pictures, talk to people that want to talk to me, play whatever weird games they have on there, and so on. After some time went by, I was starting to realize that I never really cared for Facebook, I could live without it. I deactivated my account and I've been doing better than ever without it.
I use Twitter basically everyday. There's a sole reason why I do this; it's easier to keep up with things. Instead of going to Google News and trying to find stuff that may not even be important to me, I can use Twitter and follow the things that I want to keep up with. I had a few accounts in the past that I never used, since the history of tweets on them are quite embarrassing (I wasn't very bright minded in the past) so I just leave the accounts up since no one can really find them.
I have never used Instagram, Snapchat, or anything with the sole reason of taking pictures. I'm not very interested in them because I hate taking pictures, especially of myself. I'm rather camera shy. Taking pictures of food seems rather pointless to me because I like to eat the food, not take pictures and eat it cold. That's just my opinion though.