Facetivist
A person who yells about every tiny problem on Facebook like it's the end of the world and thinks everyone else is a brainless idiot.
'Why can't they just fix traffic? It's the worst thing ever!' (from a Facetivist during rush hour.)
DM: 'You don't know what's happening? You're living under a rock!' (sent to someone who didn't reply to a post.)
Comment: 'This is the worst election ever. Everyone's stupid. I'm gonna die of stress.' (on a post about a local mayor.)