That's a rather blithe and shallow criticism of Facebook and Twitter. I could easily complain about email because of spam, but it would totally disregard its usefulness and impact. (As for Candy Crush invites and annoying selfies, Facebook actually provides tools to deal with those problems. RTFM?)
Facebook in particular has allowed me to keep in touch with a much larger social circle. It has made it easier to meet people, establish friendships, maintain distance relationships, and keep in touch with more of my extended family. It allows me to plan events quickly and on short notice, and get quick feed back on who will be attending. It helps me learn about new events or activities that I otherwise might have missed.
> Facebook in particular has allowed me to keep in touch with a much larger social circle
For me, Facebook offered a false sense of being social. The more I used it, the more I craved social interaction, leading me to use it even more. It's possible, maybe even likely, that I was "using it wrong." But after I used Facebook's tool for dealing with this problem (the Delete Account tool), I've become a more genuinely social person.
I do miss out on photos posted by my extended family. That is a genuine loss. I've probably also missed out on some events organized through Facebook. But then again, I'm making more of an effort to actively maintain relationships offline, and it's probably been a net positive.
Of course, that's just my experience. There are 1.5B active users who might disagree.
Facebook in particular has allowed me to keep in touch with a much larger social circle. It has made it easier to meet people, establish friendships, maintain distance relationships, and keep in touch with more of my extended family. It allows me to plan events quickly and on short notice, and get quick feed back on who will be attending. It helps me learn about new events or activities that I otherwise might have missed.